❯♥✐✈❡rs✐❞❛❞❡ ❋❡❞❡r❛❧ ❞❛ P❛r❛í❜❛
❈❡♥tr♦ ❞❡ ❈✐ê♥❝✐❛s ❊①❛t❛s ❡ ❞❛ ◆❛t✉r❡③❛
❉❡♣❛rt❛♠❡♥t♦ ❞❡ ▼❛t❡♠át✐❝❛
▼❡str❛❞♦ Pr♦✜ss✐♦♥❛❧ ❡♠ ▼❛t❡♠át✐❝❛
❡♠ ❘❡❞❡ ◆❛❝✐♦♥❛❧ P❘❖❋▼❆❚
❊st✉❞♦ ❙✐st❡♠át✐❝♦ ❞❛s P❛rá❜♦❧❛s
♣♦r
❍❡❧❞❡r ❘♦❞r✐❣✉❡s ▼❛❝❡❞♦
❯♥✐✈❡rs✐❞❛❞❡ ❋❡❞❡r❛❧ ❞❛ P❛r❛í❜❛
❈❡♥tr♦ ❞❡ ❈✐ê♥❝✐❛s ❊①❛t❛s ❡ ❞❛ ◆❛t✉r❡③❛
❉❡♣❛rt❛♠❡♥t♦ ❞❡ ▼❛t❡♠át✐❝❛
▼❡str❛❞♦ Pr♦✜ss✐♦♥❛❧ ❡♠ ▼❛t❡♠át✐❝❛
❡♠ ❘❡❞❡ ◆❛❝✐♦♥❛❧ P❘❖❋▼❆❚
❊st✉❞♦ ❙✐st❡♠át✐❝♦ ❞❛s P❛rá❜♦❧❛s
†♣♦r
❍❡❧❞❡r ❘♦❞r✐❣✉❡s ▼❛❝❡❞♦
s♦❜ ♦r✐❡♥t❛çã♦ ❞♦
Pr♦❢✳ ❉r✳ ◆❛♣♦❧❡ó♥ ❈❛r♦ ❚✉❡st❛
❚r❛❜❛❧❤♦ ❞❡ ❈♦♥❝❧✉sã♦ ❞❡ ❈✉rs♦ ❛♣r❡✲ s❡♥t❛❞♦ ❛♦ ❈♦r♣♦ ❉♦❝❡♥t❡ ❞♦ ❈✉rs♦ ❞❡ Pós✲●r❛❞✉❛çã♦ ❡♠ ▼❛t❡♠át✐❝❛ ❡♠ ❘❡❞❡ ◆❛❝✐♦♥❛❧ ✲ P❘❖❋▼❆❚ ✲ ❉▼ ✲ ❈❈❊◆ ✲ ❯❋P❇✱ ❝♦♠♦ r❡q✉✐s✐t♦ ♣❛r❝✐❛❧ ♣❛r❛ ♦❜t❡♥✲ çã♦ ❞♦ tít✉❧♦ ❞❡ ▼❡str❡ ❡♠ ▼❛t❡♠át✐❝❛✳
❆❣♦st♦✴✷✵✶✺ ❏♦ã♦ P❡ss♦❛ ✲ P❇
† ❖ ♣r❡s❡♥t❡ tr❛❜❛❧❤♦ ❢♦✐ r❡❛❧✐③❛❞♦ ❝♦♠ ❛♣♦✐♦ ❞❛ ❈❆P❊❙✱ ❈♦♦r❞❡♥❛çã♦ ❞❡ ❆♣❡r❢❡✐ç♦❛♠❡♥t♦ ❞❡
M141e Macedo, Helder Rodrigues.
Estudo sistemático das parábolas / Helder Rodrigues Macedo.- João Pessoa, 2015.
71f. : il.
Orientador: Napoleón Caro Tuesta Dissertação (Mestrado) - UFPB/CCEN
1. Matemática. 2. Construção das Cônicas. 3. Apolônio de Perga - matemático. 4. Geometria analítica. 5. Função
quadrática.
❆❣r❛❞❡❝✐♠❡♥t♦s
❆❣r❛❞❡ç♦ ❛ ❉❡✉s✱ ♣❡❧❛ ♦♣♦rt✉♥✐❞❛❞❡ ❞❡ r❡❛❧✐③❛çã♦ ❞❡st❡ tr❛❜❛❧❤♦ ❝♦♠ s❛ú❞❡ ❡ ❞✐s♣♦s✐çã♦ ❡ ♣♦r ❤❛✈❡r ❊❧❡ ❡s❝♦❧❤✐❞♦ ♦ ❧✐✈r♦ ❞♦ ❯♥✐✈❡rs♦ ❞❛ ▼❛t❡♠át✐❝❛ ❝♦♠♦ ✉♠
♣r❡s❡♥t❡ ❛♦ ♥♦ss♦ ❞♦♠ ♦♣♦rt✉♥✐③❛♥❞♦ ❛ ♥ós ✉♠ ♣♦✉❝♦ ❞❛ s✉❛ ❛❞♠✐rá✈❡❧ ♦❜r❛✳ ❆❣r❛❞❡ç♦✱ ❡♠ ❡s♣❡❝✐❛❧ ❛ ♠✐♥❤❛ ❡s♣♦s❛ ❙✉❡❧❧❡♥ ▼❛❝❡❞♦✱ ♣❡❧♦ ✐♥❝❡♥t✐✈♦ ❡ ♣❡❧❛ ❝♦♠♣r❡❡♥sã♦ ❞♦s t❡♠♣♦ q✉❡ ♠❡ ✜③ ❛✉s❡♥t❡ ❛♦ ♠❡ ❞❡❞✐❝❛r ❛♦s ❡st✉❞♦s ♥❛ ✈✐❞❛
❛❝❛❞ê♠✐❝❛ ❞♦ ▼❡str❛❞♦ ❡♠ ▼❛t❡♠át✐❝❛✳
❆❣r❛❞❡ç♦ ❛♦s ♠❡✉s ✜❧❤♦s✱ ▲✉❝❛s ●❛❜r✐❡❧ ❡ ❏ú❧✐❛ ▼❛❝❡❞♦ ♣❡❧❛ ❢❡❧✐❝✐❞❛❞❡ q✉❡ ♠❡ ❞ã♦ ♥❛ ♥❛t✉r❡③❛ ❧í♠♣✐❞❛ q✉❡ ❡❧❡s ♣♦ss✉❡✱ ❛ ♠✐♥❤❛ ♠ã❡ ❱✐❧♠❛ ▼❛❝❡❞♦✱ ❛♦s ♠❡✉s ✐r♠ã♦s ❍✉❣♦ ▼❛❝❡❞♦ ❡ ❍✐❧♠❛ ❱❛s❝♦♥❝❡❧♦s ▼❛❝❡❞♦ q✉❡ ❛♣♦st❛r❛♠ ♠✉✐t♦ ♥♦ ♠❡✉ tr❛❜❛❧❤♦ ❡ ♥❛ ♣❡rs❡✈❡r❛♥ç❛ ♣❛ss❛❞♦ ♣❛r❛ ♠✐♠ ❞✐❛r✐❛♠❡♥t❡ ♥❛ ❥♦r♥❛❞❛ ❛❝❛❞ê♠✐❝❛ q✉❡ ❡s❝♦❧❤✐✳ ❆❣r❛❞❡ç♦ ❛♦ ♠❡✉ ❖r✐❡♥t❛❞♦r✱ ◆❛♣♦❧❡♦♥ ❈❛r♦✱ ♣❡❧♦ ♣r❛③❡r✱ ♣r♦♥t✐❞ã♦✱ ❡♥t✉s✐❛s♠♦
❡♠ ♦r✐❡♥t❛r✲♠❡ ♥❡ss❡ tr❛❜❛❧❤♦ ❛ ❝❛❞❛ ♠♦♠❡♥t♦ ❞❡ ❢♦r♠❛ ♦❜❥❡t✐✈❛ ❡ s❡❣✉r❛ ♥❛s s✉❛s ✐♥❞❛❣❛çõ❡s ❡ ♥❛ s✉❛ ❜r✐❧❤❛♥t❡ ❝♦♠♣❡tê♥❝✐❛ ❛❝❛❞ê♠✐❝❛ q✉❡ ❛t✉❛✳
❆❣r❛❞❡ç♦ ❛ t♦❞♦s ♦s ♣r♦❢❡ss♦r❡s q✉❡ ❝♦♥tr✐❜✉ír❛♠ ♣❛r❛ ♠✐♥❤❛ ❢♦r♠❛çã♦ ❛❝❛❞ê♠✐❝❛ ❞✉r❛♥t❡ ❛ ♣ós✲❣r❛❞✉❛çã♦✱ ♣❛ss❛♥❞♦ ♣❛r❛ ♥♦s s❡✉s ❝♦♥❤❡❝✐♠❡♥t♦s ❞❡ ♠❛♥❡✐r❛
❜r✐❧❤❛♥t❡✳
❆❣r❛❞❡ç♦ ❛ t♦❞♦s ♦s ♠❡✉s ❛♠✐❣♦s ❞❛ ♣ós✲❣r❛❞✉❛çã♦✱ ❡♠ ❡s♣❡❝✐❛❧ ❛ ❋❛❜rí❝✐♦ ❞❡ P❛✉❧❛ ❡ ❆♥tô♥✐♦ ▼♦r❛✐s q✉❡ s❡♠❛♥❛❧♠❡♥t❡ ❡st❛✈❛♠ ❝♦♠✐❣♦ ❡st✉❞❛♥❞♦✱
✐♥❝❡♥t✐✈❛♥❞♦✱ ❜r✐❣❛♥❞♦✱ ❜❛t❛❧❤❛♥❞♦ ♣❛r❛ ❝♦♥str✉✐r ❡ss❡ tr❛❜❛❧❤♦✱ ❡ss❛ ♣ós✲❣r❛❞✉❛çã♦✳
❆❣r❛❞❡ç♦ ❛♦ ❉❡♣❛rt❛♠❡♥t♦ ❞❡ ▼❛t❡♠át✐❝❛ ❞❛ ❯❋P❇✱ ♣♦r ❛♣♦st❛r ♥❡ss❛ ♣ós✲❣r❛❞✉❛çã♦ ❝♦♠ ❛ ♣❛r❝❡r✐❛ ♥♦ P❘❖❋▼❆❚ ❡ ❛ ❈❆P❊❙✱ ♣❡❧♦ ❛♣♦✐♦ ✜♥❛♥❝❡✐r♦✳
❉❡❞✐❝❛tór✐❛
❘❡s✉♠♦
❊st❡ tr❛❜❛❧❤♦ ❛♣r❡s❡♥t❛ ✉♠❛ ♣r♦♣♦st❛ ❞❡ ❛❜♦r❞❛❣❡♠ q✉❡ ♣❡r♠✐t❡ t❛♥t♦ ❛♦ ♣r♦❢❡ss♦r q✉❛♥t♦ ❛♦ ❛❧✉♥♦ ❞♦ ❡♥s✐♥♦ ♠é❞✐♦ ✉♠ ❡st✉❞♦ ❤✐stór✐❝♦ ❞❛ ❝♦♥str✉çã♦ ❞❛s
❈ô♥✐❝❛s ❞❡s❡♥✈♦❧✈✐❞❛s ♣❡❧♦ ▼❛t❡♠át✐❝♦ ❡ ❆strô♥♦♠♦ ❆♣♦❧ô♥✐♦ ❞❡ P❡r❣❛ q✉❡ ❝♦♥tr✐❜✉✐✉ ✐♠❡♥s❛♠❡♥t❡ ❝♦♠ ❛s ❞❡✜♥✐çõ❡s ❤♦❥❡ ❡st✉❞❛❞❛s ♥❛ ▼❛t❡♠át✐❝❛✳ ◆♦ s❡❣✉♥❞♦ ♠♦♠❡♥t♦✱ ❥á ❜❡♠ ♠❛✐s ❞❡✜♥✐❞❛s ❛s ❈ô♥✐❝❛s ♣♦r P✐❡rr❡ ❋❡r♠❛t ♦ ❡st✉❞♦ t❡♠ ❝♦♠♦ ♦❜❥❡t✐✈♦ ❛❜♦r❞❛r ♦ ❝♦♥t❡ú❞♦ ❞❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛ ❝♦♠♦ é ❡♥s✐♥❛❞♦ ♥❛s sér✐❡s ❜ás✐❝❛s ❡ ♥❛s ❞✐s❝✐♣❧✐♥❛s ❞❡ ❈á❧❝✉❧♦✳ ◆♦ t❡r❝❡✐r♦ ♠♦♠❡♥t♦✱ ❛ ❛❜♦r❞❛❣❡♠
é ❢❡✐t❛ ❛tr❛✈és ❞♦ ❡st✉❞♦ ❞❛s ❋✉♥çõ❡s ◗✉❛❞rát✐❝❛s✱ ✉♠❛ r❡✈✐sã♦ ❞❛ ♣r✐♠❡✐r❛ sér✐❡ ❞♦ ❊♥s✐♥♦ ▼é❞✐♦✳
❆❜str❛❝t
❚❤✐s ✇♦r❦ ♣r❡s❡♥ts ♦♥❡ ♣r♦♣♦s❛❧ t❤❛t ❛❧❧♦✇s ❍✐❣❤ ❙❝❤♦♦❧ t❡❛❝❤❡rs ❛♥❞ st✉❞❡♥ts ❛ ❤✐st♦r✐❝❛❧ st✉❞② ♦❢ t❤❡ ❝♦♥str✉❝t✐♦♥ ♦❢ ❈♦♥✐❝s✱ ❞❡✈❡❧♦♣❡❞ ❜② ❆♣♦❧❧♦♥✐✉s ♦❢ P❡r❣❛✱
t❤❡ ▼❛t❤❡♠❛t✐❝✐❛♥ ❛♥❞ ❆str♦♥♦♠❡r t❤❛t ❝♦♥tr✐❜✉t❡❞ ✐♠♠❡♥s❡❧② ✇✐t❤ t❤❡ ❞❡✜♥✐t✐♦♥s ✇❡ st✉❞② ♥♦✇❛❞❛②s ✐♥ ▼❛t❤❡♠❛t✐❝s✳ ■♥ ❛ s❡❝♦♥❞ ♠♦♠❡♥t✱ ✇✐t❤ ❈♦♥✐❝s
✇❡❧❧ ❞❡✜♥❡❞ ❜② P✐❡rr❡ ❋❡r♠❛t✱ t❤❡ ❣♦❛❧ ♦❢ t❤❡ ✇♦r❦ ✐s t♦ ❛❞❞r❡ss t❤❡ ❝♦♥t❡♥t ♦❢ ❆♥❛❧②t✐❝❛❧ ●❡♦♠❡tr② ❛s t❛✉❣❤t ✐♥ t❤❡ ✐♥✐t✐❛❧ s❝❤♦♦❧ ②❡❛rs ❛♥❞ ❈❛❧❝✉❧✉s ❝♦✉rs❡s✳ ■♥
❛ t❤✐r❞ ♠♦♠❡♥t✱ t❤❡ ❛♣♣r♦❛❝❤ ✐s ❞♦♥❡ t❤r♦✉❣❤ t❤❡ st✉❞② ♦❢ ◗✉❛❞r❛t✐❝ ❋✉♥❝t✐♦♥s✱ ✉s✐♥❣ ❛ r❡✈✐❡✇ ♦❢ t❤❡ ❝♦♥t❡♥t t❛✉❣❤t ✐♥ ❙♦♣❤♦♠♦r❡ ②❡❛r ♦❢ ❍✐❣❤ ❙❝❤♦♦❧✳
❙✉♠ár✐♦
■♥tr♦❞✉çã♦ ✶
✶ ❆s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦ ❞❡ P❡r❣❛ ✶
✷ ❆ P❛rá❜♦❧❛ ♥❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛ ✺
✷✳✶ ❈♦♦r❞❡♥❛❞❛s ♥♦ P❧❛♥♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺ ✷✳✷ ❉✐stâ♥❝✐❛ ❡♥tr❡ ❞♦✐s ♣♦♥t♦s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✻ ✷✳✸ ❉✐stâ♥❝✐❛ ❡♥tr❡ ♣♦♥t♦ ❡ r❡t❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✼ ✷✳✹ ❉❡✜♥✐çã♦ ❞❡ P❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✵ ✷✳✺ ❊❧❡♠❡♥t♦s ♣r✐♥❝✐♣❛✐s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✵ ✷✳✻ ❊q✉❛çã♦ ❞❛ ♣❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✷ ✷✳✼ ❊q✉❛çõ❡s ❈❛♥ô♥✐❝❛s ❞❛ ♣❛rá❜♦❧❛ ❝♦♠ ❱ért✐❝❡ ♥❛ ♦r✐❣❡♠ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✺ ✷✳✽ ❚r❛♥s❧❛çã♦ ❞❡ ❊✐①♦s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✾ ✷✳✾ ❘♦t❛çã♦ ❞❡ ❊✐①♦s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✷✸ ✷✳✶✵ ❈♦♦r❞❡♥❛❞❛s P♦❧❛r❡s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✷✽ ✷✳✶✶ ❊q✉❛çã♦ P♦❧❛r ❞❛ P❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✶ ✷✳✶✷ ❈♦♥str✉çã♦ ❞❛ P❛rá❜♦❧❛ ♣♦r ♠❡✐♦ ❞❡ ❆rt✐❢í❝✐♦s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✷
✸ ❋✉♥çã♦ ◗✉❛❞rát✐❝❛ ✸✻
✸✳✶ ❖ ●rá✜❝♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✻ ✸✳✷ ❋♦r♠❛ ❈❛♥ô♥✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✾ ✸✳✸ ❩❡r♦✭s✮ ❞❛ ❋✉♥çã♦ ◗✉❛❞rát✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✾ ✸✳✹ ❖ ❱ért✐❝❡ ❞❛ P❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹✶ ✸✳✺ ❆ ■♠❛❣❡♠ ❞❛ ❋✉♥çã♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹✺ ✸✳✻ ❊✐①♦ ❞❡ ❙✐♠❡tr✐❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹✼ ✸✳✼ ▼♦♥♦t♦♥✐❝✐❞❛❞❡ ❞❛ ❋✉♥çã♦ ◗✉❛❞rát✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹✽ ✸✳✽ ❆ ❈❛r❛❝t❡r✐③❛çã♦ ❞❛ ❋✉♥çã♦ ◗✉❛❞rát✐❝❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✶
❘❡❢❡rê♥❝✐❛s ❇✐❜❧✐♦❣rá✜❝❛s ✺✺
▲✐st❛ ❞❡ ❋✐❣✉r❛s
✶✳✶ ❉✉♣❧✐❝❛çã♦ ❞♦ ❈✉❜♦✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✷ ✶✳✷ Pá❣✐♥❛ ❞♦ tít✉❧♦ ❞❛ ♣r✐♠❡✐r❛ ❡❞✐çã♦ ✐♠♣r❡ss❛ ❡♠ ❧❛t✐♠ ❞❛s ❈ô♥✐❝❛s
❞❡ ❆♣♦❧ô♥✐♦✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✷ ✶✳✸ ❆s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦ ❞❡ P❡r❣❛✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸ ✶✳✹ P✐❧❛r❡s ❞❛ ❝❛t❡❞r❛❧ ❞❡ ❇r❛s✐❧✐❛✳ ❋♦r♠❛ ❞❡ ✉♠ ❤✐♣❡r❜♦❧♦✐❞❡✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹ ✶✳✺ ❈♦❧✐s❡✉✱ ❡♠ ❘♦♠❛✱ t❡♠ ❢♦r♠❛ ❡❧í♣t✐❝❛✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹ ✶✳✻ P♦♥t❡ ❏✉s❝❡❧✐♥♦ ❑✉❜✐ts❝❤❡❦✱ ❡♠ ❇r❛sí❧✐❛✱ t❡♠ ❛ ❢♦r♠❛ ❞❛ ♣❛rá❜♦❧❛✳ ✳ ✹ ✶✳✼ ❚♦rr❡s ❞❡ ❘❡❢r✐❣❡r❛çã♦ ❞❡ ✉s✐♥❛s ♥✉❝❧❡❛r❡s✱ tê♠ ❛ ❢♦r♠❛ ❞♦ ❤✐♣❡r❜♦❧♦✐❞❡✳ ✹ ✷✳✶ ❈♦♦r❞❡♥❛❞❛s ♥♦ P❧❛♥♦ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✻ ✷✳✷ ❉✐stâ♥❝✐❛ ❞❡ ❞♦✐s ♣♦♥t♦s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✻ ✷✳✸ ❉✐stâ♥❝✐❛ ❞❡ ✉♠ ♣♦♥t♦ à r❡t❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✽ ✷✳✹ ❉❡✜♥✐çã♦ ❞❡ ♣❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✶ ✷✳✺ ❙❡❝çã♦ ❞♦ ❝♦♥❡ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✶✶ ✷✳✻ ❘♦t❛çã♦ ❞♦s ❡✐①♦s ❝♦♦r❞❡♥❛❞♦s✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✷✹ ✷✳✼ ❖ P♦♥t♦ ❡♠ ❈♦♦r❞❡♥❛❞❛ P♦❧❛r❡s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✵ ✷✳✽ P❛rá❜♦❧❛ ❡♠ ❈♦♦r❞❡♥❛❞❛s P♦❧❛r❡s ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✶ ✷✳✾ ❈♦♥str✉✐♥❞♦ ❛ P❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✸ ✷✳✶✵ P❛rá❜♦❧❛ ♥♦ ●❡♦❣❡❜r❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✹ ✷✳✶✶ P❛rá❜♦❧❛ ❞❡s❡♥❤❛❞❛ ❝♦♠ ❛ ré❣✉❛ ❚ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✸✺ ✸✳✶ ❊✐①♦ ❞❡ ❙✐♠❡tr✐❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✹✼ ✸✳✷ ▼♦♥♦t♦♥✐❝✐❞❛❞❡ ❞❛ P❛rá❜♦❧❛ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✳ ✺✵
■♥tr♦❞✉çã♦
▼♦t✐✈❛❞♦ ♣♦r ♣❡r❣✉♥t❛s ❢❡✐t❛s ♣♦r ❛❧✉♥♦s ❞♦ ❡♥s✐♥♦ ♠é❞✐♦ ♥♦s ❝♦♥t❡ú❞♦s ❞❡ ❋✉♥çõ❡s ◗✉❛❞rát✐❝❛s ❡ ♥❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛✱ ❡♠ ❡s♣❡❝✐❛❧✱ ♦ ❝♦♥t❡ú❞♦ ❞❡ P❛rá❜♦❧❛s✱ ♣r♦❝✉r❛♠♦s ❡s❝r❡✈❡r ♥❡ss❡ tr❛❜❛❧❤♦✱ ✉♠ ❊st✉❞♦ ❙✐st❡♠át✐❝♦ ❞❛s P❛rá❜♦❧❛s✱ ❝♦♠❡ç❛♥❞♦ ✉♠❛ ❆❜♦r❞❛❣❡♠ ❙✐♥tét✐❝❛✱ ❛♦ ❞❡st❛❝❛r ♦ ❡s♣❡t❛❝✉❧❛r tr❛❜❛❧❤♦ ❞❡ ❆♣♦❧ô♥✐♦ ❞❡ P❡r❣❛ ♣❡❧❛ ❢♦r♠❛ ❜r✐❧❤❛♥t❡ ❝♦♠♦ ✈❡✐♦ ❛ ❞❡st❛❝❛r ♦ ❝♦♥❡✱
❛s s❡❝çõ❡s ♥❡❧❡ ♣r♦❞✉③✐❞❛s ❡ à ❞❡✜♥✐çã♦ q✉❡ ♦ ♠❡s♠♦ ❝❤❛♠♦✉ ❞❡ ✧s✐♥t♦♠❛✧❞❛ ❝ô♥✐❝❛✳ ❖s s✐♥t♦♠❛s ❞❡ ✉♠❛ ❝✉r✈❛ ♣♦❞❡♠✲s❡ ❡st❡♥❞❡r ❝♦♠♦ ✉♠❛ ❝❛r❛❝t❡r✐③❛çã♦
❛❧❣é❜r✐❝❛ ❞❡ ❞❡❞✉çã♦ ❣❡♦♠étr✐❝❛✱ ✐st♦ é✱ ♥❛ ❧✐♥❣✉❛❣❡♠ ♠♦❞❡r♥❛✱ ✉♠❛ r❡❧❛çã♦ ❝❛r❛❝t❡ríst✐❝❛ ❡♥tr❡ ❛ ♦r❞❡♥❛❞❛ ❡ ❛ ❛❜s❝✐s❛ ❞❡ ✉♠ ♣♦♥t♦ ❛r❜✐trár✐♦ ❞❛ ❝✉r✈❛✳ ❆♣❡s❛r ❞❡ ❛♥t❡❝❡ss♦r❡s ❝♦♠♦ ▼❡♥❡❝♠♦✱ ❊✉❝❧✐❞❡s✱ ❞❡♥tr❡ ♦✉tr♦s✱ tr❛❜❛❧❤❛r❡♠ ❝♦♠
❛s ❝ô♥✐❝❛s✱ ❛ ❛❜♦r❞❛❣❡♠ ❤✐stór✐❝❛ ❞❡ss❡ ❝♦♥t❡ú❞♦ ❢♦✐ ❡♥❢❛t✐③❛❞♦ ❛ ♣❛rt✐r ❞♦s tr❛❜❛❧❤♦s ❞❡ ❆♣♦❧ô♥✐♦✱ ❡♠ ❡s♣❡❝✐❛❧ s✉❛ ♦❜r❛ ♣r✐♠❛ ❆s ❈ô♥✐❝❛s ♣♦r s❡r✈✐r ❞❡ ❡st✉❞♦s ♣❛r❛ P✐❡rr❡ ❋❡r♠❛t ✐♥tr♦❞✉③✐r ♥❛ ♠❛t❡♠át✐❝❛ ❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛✳ ❙❡❣✉❡✲s❡ ♥♦ s❡❣✉♥❞♦ ♠♦♠❡♥t♦ ❛ ❛❜♦r❞❛❣❡♠ ❞❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛ ❢❡✐t❛ ♣♦r P✐❡rr❡ ❋❡r♠❛t✱ q✉❛♥❞♦ ♣❛ss♦✉ ❛ ❡s❝r❡✈❡r ❛s s❡❝çõ❡s ❝ô♥✐❝❛s ♣♦r ♠❡✐♦s ❞❡ ❡q✉❛çõ❡s ❞♦ s❡❣✉♥❞♦ ❣r❛✉ ♥❛s ❝♦♦r❞❡♥❛❞❛s ✭①✱ ②✮✳ ❚r❛❜❛❧❤❛♠♦s ❛ ❞❡✜♥✐çã♦✱ ♦s ❡❧❡♠❡♥t♦s ❞❛
P❛rá❜♦❧❛✱ ❛s ❡q✉❛çõ❡s ❝❛♥ô♥✐❝❛s✱ ❛s ❡q✉❛çõ❡s ❞❡ tr❛♥s❧❛çã♦ ❡ r♦t❛çã♦ ❡ ❛ ❢♦r♠❛ ♣♦❧❛r ❞❛ ♣❛rá❜♦❧❛✳ P♦r ✜♠✱ ♥❡ss❡ ❝❛♣ít✉❧♦✱ ✉t✐❧✐③❛♥❞♦✲❡ ❞❛s ✐♥❢♦r♠❛çõ❡s ♦❜t✐❞❛s✱ ❝♦♥str✉í♠♦s ❛ ♣❛rá❜♦❧❛ ❛tr❛✈és ❞♦ s♦❢t✇❛r❡ ●❡♦❣❡❜r❛✱ ♠♦str❛♠♦s ❝♦♠♦ ❝♦♥str✉✐r ❛
♣❛rá❜♦❧❛ ♣♦r ♠❡✐♦ ❞❡ ❞♦❜r❛❞✉r❛s ❝♦♠ ♣❛♣❡❧✱ ♠✉✐t♦ ✐♥t❡r❡ss❛♥t❡ ♣❛r❛ ❛♣❧✐❝❛çã♦ ♥❛ s❛❧❛ ❞❡ ❛✉❧❛ ❡ ♣❡❧♦ ❞❡s❡♥❤♦ ❣❡♦♠étr✐❝♦ ❛tr❛✈és ❞❛ ré❣✉❛ ❚ ❡ ✉♠❛ ♣r❛♥❝❤❡t❛ ❞❡
❞❡s❡♥❤♦✳
◆♦ t❡r❝❡✐r♦ ❝❛♣ít✉❧♦✱ ❛❣♦r❛ ❥á ❜❡♠ ❞❡✜♥✐❞❛ ❛ ♣❛rá❜♦❧❛✱ ✜③❡♠♦s ✉♠ ❡st✉❞♦ ❞❛ ❋✉♥çã♦ ◗✉❛❞rát✐❝❛ ❞❡s❞❡ ❛ ❝♦♥str✉çã♦ ❞♦ s❡✉ ❣rá✜❝♦ ♣♦r ♠❡✐♦ ❞❡ ❛tr✐❜✉✐çã♦ à ✈❛r✐á✈❡❧x✱ s❡✉s ❝♦♥❝❡✐t♦s ✐♥✐❝✐❛✐s✱ s✉❛ ❢♦r♠❛ ❝❛♥ô♥✐❝❛ ❡✱ ❛tr❛✈és ❞❡❧❛ ♦s ③❡r♦s ❞❛
❢✉♥çã♦ q✉❛❞rát✐❝❛✱ ❜❡♠ ❝♦♠♦ ❛ ❛♣r❡s❡♥t❛çã♦ ❞❛ ❢ór♠✉❧❛ ❞❡ ❇❤ás❦❛r❛✳ ❆✐♥❞❛ ♥❛ ❢♦r♠❛ ❝❛♥ô♥✐❝❛✱ ❛♣r❡s❡♥t❛♠♦s ♦ ✈ért✐❝❡ ❞❛ ♣❛rá❜♦❧❛ ❝♦♠ s❡✉ ✈❛❧♦r ♠á①✐♠♦ ♦✉ ♠í♥✐♠♦✱ ❛ ✐♠❛❣❡♠ ❞❛ ❢✉♥çã♦✱ s❡✉ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ ❡ ✉♠ ❡st✉❞♦ ❞❛ ♠♦♥♦t♦♥✐❝✐❞❛❞❡
♣❛r❛ ♠♦str❛r ♦ ♠♦♠❡♥t♦ ❞❡ ❝r❡s❝✐♠❡♥t♦ ❡ ❞❡❝r❡s❝✐♠❡♥t♦ ❞❡ ✉♠❛ ♣❛rá❜♦❧❛✳ ❋✐♥❛❧♠❡♥t❡✱ ❛ ❝❛r❛❝t❡r✐③❛çã♦ ❞❛ ♣❛rá❜♦❧❛ ♣♦r ♠❡✐♦ ❞❛ ♣r♦❣r❡ssã♦ ❛r✐t♠ét✐❝❛ ❞❡
s❡❣✉♥❞❛ ♦r❞❡♠✱ ❝♦♥❝r❡t✐③❛♥❞♦ ❛✐♥❞❛ ♠❛✐s ♦ ❡st✉❞♦ ❞❡ss❡ ❝♦♥t❡ú❞♦✳
❈❛♣ít✉❧♦ ✶
❆s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦ ❞❡ P❡r❣❛
❆♣♦❧ô♥✐♦ ♥❛s❝❡✉ ❡♠ P❡r❣❛✱ ❝✐❞❛❞❡ ❛♦ s✉❧ ❞♦ q✉❡ ❤♦❥❡ é ❛ ❚✉rq✉✐❛ ✭✷✻✷✲✶✾✵ ❛✳❈✳✮✱ ❝♦♥❤❡❝✐❞♦ ❥á ♥❛ ❆♥t✐❣✉✐❞❛❞❡ ❝♦♠♦ ♦ ●r❛♥❞❡ ●❡ô♠❡tr❛✱ ❢♦✐ ✉♠ ❝é❧❡❜r❡ ♠❛t❡♠át✐❝♦
❡ ❛strô♥♦♠♦ q✉❡ ✈✐✈❡✉ ❣r❛♥❞❡ ♣❛rt❡ ❞❛ s✉❛ ✈✐❞❛ ❡♠ ❆❧❡①❛♥❞r✐❛✱ ♣r✐♠❡✐r♦ ❝♦♠♦ ❞✐s❝í♣✉❧♦ ❡ ♠❛✐s t❛r❞❡ ❝♦♠♦ ♣r♦❢❡ss♦r ♥❛ ❡s❝♦❧❛ ❞♦s s✉❝❡ss♦r❡s ❞❡ ❊✉❝❧✐❞❡s✳ ❙❡✐s ❞❛s ♦❜r❛s ❞❡ ❆♣♦❧ô♥✐♦ sã♦ r❡❢❡r✐❞❛s ♥♦ ❚❡s♦✉r♦ ❞❛ ❆♥á❧✐s❡✱ ❞❛ ❈♦❧❡çã♦ ▼❛t❡♠át✐❝❛ ❞❡ P❛♣✉s✿ ❙♦❜r❡ ❛ ❙❡❝çã♦ ❞✉♠❛ ❘❛③ã♦✱ ❙♦❜r❡ ❛ ❙❡❝çã♦ ❞✉♠❛ ➪r❡❛✱ ❙♦❜r❡ ❛ ❙❡❝çã♦ ❉❡t❡r♠✐♥❛❞❛✱ ❙♦❜r❡ ❛s ❚❛♥❣ê♥❝✐❛s✱ ❙♦❜r❡ ❛s ■♥❝❧✐♥❛çõ❡s ❡ ❙♦❜r❡ ♦s ▲✉❣❛r❡s P❧❛♥♦s✳
P❛r❛ ❛ ♠❛✐♦r✐❛ ❞♦s ❤✐st♦r✐❛❞♦r❡s ❞❛ ▼❛t❡♠át✐❝❛✱ ❛s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦ ❝♦♥st✐t✉❡♠ ✉♠ tr❛t❛❞♦ ❞❡ ❣r❛♥❞❡ ❛♠♣❧✐t✉❞❡ ❡ ♣r♦❢✉♥❞✐❞❛❞❡✳ ❚r❛t❛✲s❡ ❞❡ ✉♠❛ ♦❜r❛
❡①t❡♥s❛ ❡ r✐❣♦r♦s❛✱ ❝♦♠♣❛rá✈❡❧ ❛♦s ❊❧❡♠❡♥t♦s ❞❡ ❊✉❝❧✐❞❡s ♣❡❧♦ s❡✉ ❝♦♥t❡ú❞♦ ❡ r✐❣♦r✳ ❊ss❛ ♦❜r❛ ♣❛ss♦✉ ❛ s❡r ♦ tr❛t❛❞♦ ♣♦r ❡①❝❡❧ê♥❝✐❛ s♦❜r❡ ❛s s❡❝çõ❡s ❝ô♥✐❝❛s ❡
s✉❜st✐t✉✐✉ ♦s ❡s❝r✐t♦s ❛♥t❡r✐♦r❡s ❞❡ ▼❡♥❡❝♠♦✱ ❆r✐st❡✉ ❡ ❊✉❝❧✐❞❡s✱ ♣♦✐s ❆♣♦❧ô♥✐♦ ❡st✉❞♦✉ tã♦ ♣r♦❢✉♥❞❛♠❡♥t❡ ❛s ♣r♦♣r✐❡❞❛❞❡s ❞❛s ❝ô♥✐❝❛s q✉❡ t♦r♥♦✉ ❛s ♦❜r❛s
❛♥t❡r✐♦r❡s ♦❜s♦❧❡t❛s✳
❆ ♦r✐❣❡♠ ❞❛s ❝ô♥✐❝❛s ❡stá r❡❧❛❝✐♦♥❛❞❛ ❛♦ ♣r♦❜❧❡♠❛ ❞❛ ❞✉♣❧✐❝❛çã♦ ❞♦ ❝✉❜♦ q✉❡ ❝♦♥s✐st❡ ❡♠ ❝♦♥str✉✐r✱ ❝♦♠ ♦ ✉s♦ ❞❡ ré❣✉❛ ❡ ❝♦♠♣❛ss♦ ❞❛❞❛ ❛ ❛r❡st❛ ❞❡ ✉♠ ❝✉❜♦✱ ❛
❛r❡st❛ ❞❡ ✉♠ s❡❣✉♥❞♦ ❝✉❜♦ ❝✉❥♦ ✈♦❧✉♠❡ é ♦ ❞♦❜r♦ ❞♦ ❛♥t❡r✐♦r ✭❋✐❣✉r❛ ✶✳✶✮ ➱ ❞✐❢í❝✐❧ ❛t✉❛❧♠❡♥t❡ ❝♦♠♣r❡❡♥❞❡r ❝♦♠♦ ❆♣♦❧ô♥✐♦ ♣♦❞✐❛ ❞❡s❝♦❜r✐r ❡ ♣r♦✈❛r ❝❡♥t❡♥❛s
❞❡ ❜❡❧♦s ❡ ❞✐❢í❝❡✐s t❡♦r❡♠❛s s❡♠ ♦ s✐♠❜♦❧✐s♠♦ ❛❧❣é❜r✐❝♦ ♠♦❞❡r♥♦✱ ♥♦ ❡♥t❛♥t♦✱ ❡❧❡ ❢❡③✳ ❊♠❜♦r❛ s❡ tr❛t❡ ❞❡ ✉♠❛ ♦❜r❛ ❡①t❡♥s❛ ❡ ❞❡ ❞✐❢í❝✐❧ ❧❡✐t✉r❛✱ ♣❛r❛ q✉❡♠ ❡stá ❢❛♠✐❧✐❛r✐③❛❞♦ ❝♦♠ ♦s ♠ét♦❞♦s ♠♦❞❡r♥♦s✱ ❡st❡ tr❛t❛❞♦ ❡stá ❛ ♣❛r ❞♦ q✉❡ ♠❛✐s
❜r✐❧❤❛♥t❡ ❝♦♥❤❡❝❡♠♦s ❞❛ ❣❡♦♠❡tr✐❛ ❛♥t✐❣❛✳
❆♣♦❧ô♥✐♦ ❞❡✜♥✐✉ ❛s s❡❝çõ❡s ❝ô♥✐❝❛s ❞❡ ♠♦❞♦ ❞✐❢❡r❡♥t❡ ❞♦ q✉❡ t✐♥❤❛ s✐❞♦ ❛❞♦t❛❞♦ ♣❡❧♦s s❡✉s ❛♥t❡❝❡ss♦r❡s✳ ❈♦♠ ✉♠❛ ✈✐sã♦ ❣❡♦♠étr✐❝❛ ✐♥♦✈❛❞♦r❛✱ ❞❡♠♦♥str♦✉ q✉❡
♥ã♦ ❡r❛ ♥❡❝❡ssár✐❛ ❛ r❡str✐çã♦ ❞❛ ♣❡r♣❡♥❞✐❝✉❧❛r✐❞❛❞❡ ❞♦ ♣❧❛♥♦ ❞❡ ✐♥t❡rs❡❝çã♦ à ❣❡r❛tr✐③ ❞♦ ❝♦♥❡✱ ❡ ❛✐♥❞❛ q✉❡ ❞❡ ✉♠ ú♥✐❝♦ ❝♦♥❡ ❡r❛ ♣♦ssí✈❡❧ ♦❜t❡r ❛s três ❡s♣é❝✐❡s
❞❡ s❡❝çõ❡s ❝ô♥✐❝❛s ✈❛r✐❛♥❞♦ ❛♣❡♥❛s ❛ ✐♥❝❧✐♥❛çã♦ ❞♦ ♣❧❛♥♦ ❞❡ s❡❝çã♦✳ ❊st❡ ❢♦✐ ✉♠ ♣❛ss♦ ✐♠♣♦rt❛♥t❡✱ ♣♦✐s ❝♦♥tr✐❜✉✐✉ ♣❛r❛ r❡❧❛❝✐♦♥❛r ♦s três t✐♣♦s ❞❡ ❝✉r✈❛s✿ ❛ ❡❧✐♣s❡✱
❋✐❣✉r❛ ✶✳✶✿ ❉✉♣❧✐❝❛çã♦ ❞♦ ❈✉❜♦✳
❋✐❣✉r❛ ✶✳✷✿ Pá❣✐♥❛ ❞♦ tít✉❧♦ ❞❛ ♣r✐♠❡✐r❛ ❡❞✐çã♦ ✐♠♣r❡ss❛ ❡♠ ❧❛t✐♠ ❞❛s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦✳
❛ ♣❛rá❜♦❧❛ ❡ ❛ ❤✐♣ér❜♦❧❡✳ ❖✉tr❛ ❣❡♥❡r❛❧✐③❛çã♦ ✐♠♣♦rt❛♥t❡ ❝♦♥t✐❞❛ ♥❡st❡ tr❛t❛❞♦ é ♦ ❢❛t♦ ❞❡ q✉❡ ♦ ❝♦♥❡ ♥ã♦ ♣r❡❝✐s❛r s❡r r❡t♦❀ ❆♣♦❧ô♥✐♦ ❢♦✐ ♦ ♣r✐♠❡✐r♦ ❣❡ô♠❡tr❛ ❛ ♠♦str❛r q✉❡ ❛s ♣r♦♣r✐❡❞❛❞❡s ❞❡ss❛s ❝✉r✈❛s ♥ã♦ ❡r❛♠ ❞✐❢❡r❡♥t❡s ❝♦♥❢♦r♠❡ ❢♦ss❡♠ ❝♦rt❛❞♦s ♦s ❝♦♥❡s ♦❜❧íq✉♦s ♦✉ r❡t♦s✳ ❚❛♠❜é♠ ❛❧❛r❣♦✉ ♦s s❡✉s ❡st✉❞♦s ❛♦ s✉❜st✐t✉✐r
♦ ❝♦♥❡ ❞❡ ✉♠❛ só ❢♦❧❤❛ ♣♦r ✉♠ ❞✉♣❧♦✱ ♦ q✉❡ ❢❡③ ❝♦♠ q✉❡ ❛♣r❡s❡♥t❛ss❡ ❛s ❝✉r✈❛s ❛♥t✐❣❛s ❞❡ ❢♦r♠❛ ♠❛✐s ♣ró①✐♠❛ ❞♦ ♣♦♥t♦ ❞❡ ✈✐st❛ ✉s❛❞❛ ❤♦❥❡✳
❆ ♦❜r❛ ❆s ❈ô♥✐❝❛s✱ ❞❡ ❆♣♦❧ô♥✐♦✱ ❢♦✐ ❞✉r❛♠❡♥t❡ ❝r✐t✐❝❛❞❛ ♣♦r ❛❧❣✉♥s sá❜✐♦s ❞❡ s✉❛ é♣♦❝❛✱ q✉❡ ♥ã♦ ✈✐❛♠ ♥❡ss❡ ❡st✉❞♦ ♥❡♥❤✉♠❛ ❛♣❧✐❝❛çã♦ ♥♦ ♠✉♥❞♦ r❡❛❧✳ ▼❛s ♦ t❡♠♣♦
s❡ ✐♥❝✉♠❜✐✉ ❞❡ ♠♦str❛r q✉❡ ❡ss❡s sá❜✐♦s ❡st❛✈❛♠ ❡♥❣❛♥❛❞♦s✿ ♣♦r ✈♦❧t❛ ❞❡ ✶✻✵✺✱ ♦ ❛strô♥♦♠♦ ❛❧❡♠ã♦ ❏♦❤❛♥♥❡s ❑❡♣❧❡r ❞❡s❝♦❜r✐✉ q✉❡ ♦s ♣❧❛♥❡t❛s ❞❡s❝r❡✈❡♠ ór❜✐t❛s ❡❧í♣t✐❝❛s ❡♠ t♦r♥♦ ❞♦ ❙♦❧❀ ❡♠ ✶✻✸✷✱ ●❛❧✐❧❡✉ ●❛❧✐❧❡✐ ❞❡s❝r❡✈❡✉ ❝♦♠♦ ♣❛r❛❜ó❧✐❝❛ ❛
tr❛❥❡tór✐❛ ❞❡ ♣r♦❥ét❡✐s❀ ❡♠ ✶✻✻✷✱ ❘♦❜❡rt ❇♦②❧❡ ❞❡s❝♦❜r✐✉ q✉❡✱ s♦❜ t❡♠♣❡r❛t✉r❛ ❝♦♥st❛♥t❡✱ ❛ ❢✉♥çã♦ q✉❡ ❡①♣r❡ss❛ ❛ r❡❧❛çã♦ ❡♥tr❡ ♦ ✈♦❧✉♠❡ ❞❡ ✉♠❛ ♠❛ss❛ ✜①❛ ❞❡
❣ás ❡ ❛ ♣r❡ssã♦ ❡①❡r❝✐❞❛ s❡❜r❡ ❡❧❛ é ❤✐♣❡r❜ó❧✐❝❛✳
❋✐❣✉r❛ ✶✳✸✿ ❆s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦ ❞❡ P❡r❣❛✳
❆♣❡s❛r ❞❛ ♥♦t❛❜✐❧✐❞❛❞❡ ❞❛s ❈ô♥✐❝❛s✱ t❛♥t♦ ♣❡❧♦ ❝♦♥t❡ú❞♦ ❝♦♠♦ ♣❡❧❛ ✐♥♦✈❛çã♦ ❞♦s ♠ét♦❞♦s✱ ❆♣♦❧ô♥✐♦ ✜❝♦✉ ♥♦s ❡st✉❞♦s ❞❛s ❝✉r✈❛s ♠✉✐t♦ ❛q✉é♠ ❞❛ ✢❡①✐❜✐❧✐❞❛❞❡ ❡ ❞❛
❣❡♥❡r❛❧✐❞❛❞❡ ❞❡ tr❛t❛♠❡♥t♦ ❞❛❞♦ ♠❛✐s t❛r❞❡ ♣♦r ❘❡♥ê ❉❡s❝❛rt❡s ✭✶✺✾✻✲✶✻✺✾✮ ❡ P✐❡rr❡ ❋❡r♠❛t ✭✶✻✵✶✲✶✻✻✺✮✳ ❆s ❧✐♠✐t❛çõ❡s ❞❛ ➪❧❣❡❜r❛ ●❡♦♠étr✐❝❛ ❡ ❛ ❛✉sê♥❝✐❛ ❞❡
s✐♠❜♦❧✐s♠♦ ❛❧❣é❜r✐❝♦ ❢♦r❛♠ ♦s ❢❛t♦r❡s ❞❡❝✐s✐✈♦s q✉❡ ✐♠♣❡❞✐r❛♠ ❆♣♦❧ô♥✐♦ ❞❡ t❡r s✐❞♦ ♦ ❝r✐❛❞♦r ❞❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛✳ ❋❛t♦ ❡ss❡ ❞❛❞♦ ❛ ❋❡r♠❛t ❡ ❉❡s❝❛rt❡s✳ ❍♦❥❡✱ ♣♦❞❡♠♦s ❝♦♥st❛t❛r ❛ ♣r❡s❡♥ç❛ ❞❛s ❝ô♥✐❝❛s ❡♠ ♠✉✐t❛s ♦✉tr❛s s✐t✉❛çõ❡s ❞♦
♠✉♥❞♦ r❡❛❧✱ ❝♦♠♦ ♥❛ ❝♦♥str✉çã♦ ❞❛s ❛♥t❡♥❛s ♣❛r❛❜ó❧✐❝❛s✱ ❡s♣❡❧❤♦s ❡ ❧❡♥t❡s ♣❛r❛❜ó❧✐❝♦s ♦✉ ❤✐♣❡r❜ó❧✐❝♦s❀ ♥❛s tr❛❥❡tór✐❛s ❡❧í♣t✐❝❛s✱ ♣❛r❛❜ó❧✐❝❛s ♦✉ ❤✐♣❡r❜ó❧✐❝❛s
❞❡ ❛str♦s ❝❡❧❡st❡s✱ ❞❡♥tr❡ ♦✉tr♦s✳
❱❡❥❛ ❛❧❣✉♠❛s ❝ô♥✐❝❛s q✉❡ ❛♣❛r❡❝❡♠ ♥❛s ✜❣✉r❛s ❛❜❛✐①♦✿
❉❛s ❈ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦✱ ❢❛r❡♠♦s ✉♠ ❡st✉❞♦ s✐st❡♠át✐❝♦ r❡❧❛t✐✈♦ às P❛rá❜♦❧❛s ♥♦
❋✐❣✉r❛ ✶✳✹✿ P✐❧❛r❡s ❞❛ ❝❛t❡❞r❛❧ ❞❡
❇r❛s✐❧✐❛✳ ❋♦r♠❛ ❞❡ ✉♠ ❤✐♣❡r❜♦❧♦✐❞❡✳ ❋✐❣✉r❛ ✶✳✺✿ ❈♦❧✐s❡✉✱ ❡♠ ❘♦♠❛✱ t❡♠❢♦r♠❛ ❡❧í♣t✐❝❛✳
❋✐❣✉r❛ ✶✳✻✿ P♦♥t❡ ❏✉s❝❡❧✐♥♦ ❑✉❜✐ts✲ ❝❤❡❦✱ ❡♠ ❇r❛sí❧✐❛✱ t❡♠ ❛ ❢♦r♠❛ ❞❛ ♣❛✲ rá❜♦❧❛✳
❋✐❣✉r❛ ✶✳✼✿ ❚♦rr❡s ❞❡ ❘❡❢r✐❣❡r❛çã♦ ❞❡ ✉s✐♥❛s ♥✉❝❧❡❛r❡s✱ tê♠ ❛ ❢♦r♠❛ ❞♦ ❤✐✲ ♣❡r❜♦❧♦✐❞❡✳
❛❞✈❡♥t♦ ❞❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛ ❡ ❛s ❋✉♥çõ❡s ◗✉❛❞rát✐❝❛s✱ ❡st❡✱ ♥♦ ❝♦♥t❡ú❞♦ ❞❡ ❋✉♥çõ❡s✳ ❆tr❛✈és ❞❛s ♥♦t❛çõ❡s ♠♦❞❡r♥❛s ❛♣r❡s❡♥t❛❞❛s ♣♦r ❋❡r♠❛t ❡ ❉❡s❝❛rt❡s ✐r❡♠♦s ❞❡s❡♥✈♦❧✈❡r ❛s t❡♦r✐❛s s♦❜r❡ ❛s ❝ô♥✐❝❛s ♥❛s ♣ró①✐♠❛s s❡çõ❡s✱ ♣♦ré♠✱ ♠✉✐t♦
♣ró①✐♠❛s ❞♦ q✉❡ ❢♦✐ ❢❡✐t♦ ♣♦r ❆♣♦❧ô♥✐♦ ♥❛q✉❡❧❛ é♣♦❝❛✳
❈❛♣ít✉❧♦ ✷
❆ P❛rá❜♦❧❛ ♥❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛
❯♠ ❞♦s ♠❛✐♦r❡s ❝♦♥tr✐❜✉✐♥t❡s ♣❛r❛ ❝♦♥str✉çã♦ ❞❛ ●❡♦♠❡tr✐❛ ❆♥❛❧ít✐❝❛✱ ❞♦ ❈á❧❝✉❧♦ ❉✐❢❡r❡♥❝✐❛❧✱ ❞♦ ❈á❧❝✉❧♦ ■♥t❡❣r❛❧ ❡ ❞❛ ❚❡♦r✐❛ ❞❛s Pr♦❜❛❜✐❧✐❞❛❞❡ ❢♦✐ P✐❡rr❡ ❋❡r♠❛t✳
❙❡♠ s♦♠❜r❛ ❞❡ ❞ú✈✐❞❛✱ ❡❧❡ ❢♦✐ ♦ ❣r❛♥❞❡ ♥♦♠❡ ❞❛ ❢❛s❡ ✐♥✐❝✐❛❧ ❞❛ ♠♦❞❡r♥❛ ❚❡♦r✐❛ ❞♦s ◆ú♠❡r♦s✳ ❋❡r♠❛t ❝✉rs♦✉ ❉✐r❡✐t♦ ❡♠ ❚♦✉❧♦✉s❡ ♥❛ ❋r❛♥ç❛ ❡♠ ❝✉❥♦ ♣❛r❧❛♠❡♥t♦
❝♦♠❡ç♦✉ ❛ tr❛❜❛❧❤❛r ♥♦ ❛♥♦ ❞❡ ✶✻✸✶✱ ♣r✐♠❡✐r♦ ❝♦♠♦ ❛❞✈♦❣❛❞♦ ❡✱ ♣♦st❡r✐♦r♠❡♥t❡ ❝♦♠♦ ❝♦♥s❡❧❤❡✐r♦✳ ❈♦♠♦ ❞♦♠✐♥❛✈❛ ❛s ❞✉❛s ❛t✐✈✐❞❛❞❡s✱ ♥✐♥❣✉é♠ ♣♦❞❡r✐❛ ✐♠❛❣✐♥❛r q✉❡ s✉❛ ✈♦❝❛çã♦ ❝✉❧t✐✈❛❞❛ ❝♦♠ ❣r❛♥❞❡ t❛❧❡♥t♦ ♥❛s ❤♦r❛s ❞❡ ❧❛③❡r ❡r❛ ❛ ▼❛t❡♠át✐❝❛✳
P❡❧❛ s✉❛ ❝♦♥❞✐çã♦ ❞❡ ❛♠❛❞♦r ♥❛ ár❡❛ ❞❛ ▼❛t❡♠át✐❝❛ ❋❡r♠❛t✱ r❡❝✉s❛✈❛✲s❡ s✐st❡♠❛t✐❝❛♠❡♥t❡ ❛ ♣✉❜❧✐❝❛r s✉❡s tr❛❜❛❧❤♦s ❡✱ s❡ ❡ss❡s sã♦ r❡❝♦♥❤❡❝✐❞♦s ❤♦❥❡✱ é
♣♦rq✉❡ ✜❝❛r❛♠ r❡❣✐str❛❞♦s ❡♠ ♠❛r❣❡♥s ❞❡ ❧✐✈r♦s✱ ❢♦❧❤❛s ❛✈✉❧s❛s ❡ ❝❛rt❛s✳ ❆ ●❡♦♠❡tr✐❛ ❞❡ P✐❡rr❡ ❋❡r♠❛t ❛ ♣❛rt✐r ❞❡ ✶✻✷✾ ❡♠♣r❡❡♥❞❡✉ ❛ r❡❝♦♥str✉✐r ❛ ♦❜r❛
❞❡ ❆♣♦❧ô♥✐♦ ▲✉❣❛r❡s P❧❛♥♦s✱ ♠❡❞✐❛♥t❡ ❛ r❡❢❡rê♥❝✐❛s ❝♦♥t✐❞❛s ♥❛ ❈♦❧❡çã♦ ▼❛t❡♠át✐❝❛✱ ❞❡ P❛♣✉s✳ ❋♦✐ ✉♠ ♣❡q✉❡♥♦ tr❛t❛❞♦ ♣✉❜❧✐❝❛❞♦ ❡♠ ✶✻✼✾✱ ❝♦♥❤❡❝✐❞♦ ❝♦♠♦ ■♥tr♦❞✉çã♦ ❛♦s ❧✉❣❛r❡s ♣❧❛♥♦s ❡ só❧✐❞♦s✳ ◆❡ss❡ tr❛t❛❞♦✱ ❛♦ ❛♥✉♥❝✐❛r q✉❡ ❞❛❞❛
✉♠❛ ❡q✉❛çã♦ ❝♦♠ ❞✉❛s ✈❛r✐á✈❡✐s✱ ✉♠❛ ❞❡st❛s ❞❡s❝r❡✈❡ ✉♠❛ r❡t❛ ♦✉ ✉♠❛ ❝✉r✈❛✱ r❡✈❡❧❛✈❛ ❡❧❡ ❡♥tã♦✱ ❡stá ❞❡ ♣♦ss❡ ❞♦ ♣r✐♥❝í♣✐♦ ❢✉♥❞❛♠❡♥t❛❧ ❞♦ ♥♦✈♦ ♠ét♦❞♦✳ ❊❧❡
♣ró♣r✐♦ ♠♦str♦✉ q✉❡ ✉♠❛ ❡q✉❛çã♦ ❣❡r❛❧ ax+by =c ❡♠ q✉❡ a6= 0 ♦✉ b6= 0 r❡♣r❡s❡♥t❛✈❛ ✉♠❛ r❡t❛❀ ❡ q✉❡ ❡q✉❛çõ❡s ❞♦ s❡❣✉♥❞♦ ❣r❛✉ ❡♠ ❞✉❛s ✈❛r✐á✈❡✐s ♣♦❞❡♠
s❡r ❝ír❝✉❧♦s✱ ❡❧✐♣s❡s✱ ♣❛rá❜♦❧❛s ♦✉ ❤✐♣ér❜♦❧❡s✳
❱❡r❡♠♦s ❡♥tã♦ ❞❛s ❝ô♥✐❝❛s ❞❡ ❆♣♦❧ô♥✐♦ ✉♠ ❡st✉❞♦ ❆♥❛❧ít✐❝♦ ❞❛ P❛rá❜♦❧❛✱ ❛ ❝♦♠❡ç❛r ♣♦r ❛❧❣✉♠❛s ❞❡✜♥✐çõ❡s ♣r❡❧✐♠✐♥❛r❡s✿
✷✳✶ ❈♦♦r❞❡♥❛❞❛s ♥♦ P❧❛♥♦
❉❛❞♦ ✉♠ ♣♦♥t♦ P ❞♦ ♣❧❛♥♦ ❝❛rt❡s✐❛♥♦✱ ❝❤❛♠❛✲s❡ ❞❡ ✧♣r♦❥❡çã♦ ♦rt♦❣♦♥❛❧ ❞❡ P s♦❜r❡ ✉♠ ❞♦s ❡✐①♦s Ox ♦✉Oy✧❛ ✐♥t❡rs❡❝çã♦ ❞❡ss❡ ❡✐①♦ ❝♦♠ ❛ r❡t❛ ♣❡r♣❡♥❞✐❝✉❧❛r ❛
❡❧❡✱ tr❛ç❛❞♦ ♣♦r P✳ ❖♥❞❡✿
✷✳✷✳ ❉■❙❚➶◆❈■❆ ❊◆❚❘❊ ❉❖■❙ P❖◆❚❖❙
❋✐❣✉r❛ ✷✳✶✿ ❈♦♦r❞❡♥❛❞❛s ♥♦ P❧❛♥♦
• P1 é ❛ ♣r♦❥❡çã♦ ♦rt♦❣♦♥❛❧ ❞❡ P s♦❜r❡ ♦ ❡✐①♦ Ox✳
• P2 é ❛ ♣r♦❥❡çã♦ ♦rt♦❣♦♥❛❧ ❞❡ P s♦❜r❡ ♦ ❡✐①♦ Oy✳
• ❉✐③❡♠♦s q✉❡ ❛s ❝♦♦r❞❡♥❛❞❛s ❞♦ ♣♦♥t♦ P sã♦ ♦s ♥ú♠❡r♦s ❛ss♦❝✐❛❞♦s ❛ P1 ❡ P2 ♥♦s ❡✐①♦ Ox ❡ Oy✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✳ P♦rt❛♥t♦✱ r❡♣r❡s❡♥t❛♠♦s ♦ ♣♦♥t♦ P ❞❛
❢♦r♠❛ P = (P1, P2)✳
✷✳✷ ❉✐stâ♥❝✐❛ ❡♥tr❡ ❞♦✐s ♣♦♥t♦s
◆❛ ✜❣✉r❛ ✭✷✳✷✮✱ t❡♠♦s ✉♠ s❡❣♠❡♥t♦ AB ♥ã♦ ♣❛r❛❧❡❧♦ ❛ ♥❡♥❤✉♠ ❞♦s ❡✐①♦s
❝♦♦r❞❡♥❛❞♦s✳
❋✐❣✉r❛ ✷✳✷✿ ❉✐stâ♥❝✐❛ ❞❡ ❞♦✐s ♣♦♥t♦s
❖ tr✐â♥❣✉❧♦ ❆❇❈✱ ❝♦♠ A= (xA, yA), B = (xB, yB) ❡ C = (xC, yC)✱ é r❡tâ♥❣✉❧♦ ❡♠
✷✳✸✳ ❉■❙❚➶◆❈■❆ ❊◆❚❘❊ P❖◆❚❖ ❊ ❘❊❚❆
❈✳
AC é ♣❛r❛❧❡❧♦ ❛♦ ❡✐①♦ Ox✳ ❆ss✐♠✱ ♦ ❝♦♠♣r✐♠❡♥t♦ ❆❈ é ✐❣✉❛❧ ❛♦ ❝♦♠♣r✐♠❡♥t♦ ❞❛
♣r♦❥❡çã♦ ♦rt♦❣♦♥❛❧ ❞❡ AC s♦❜r❡ ♦ ❡✐①♦ Ox✱ ♦✉ s❡❥❛✱AC =|xB−xA|. ❆♥❛❧♦❣❛♠❡♥t❡✱ CB é ♣❛r❛❧❡❧♦ ❛♦ ❡✐①♦ Oy❀ ❧♦❣♦✿ CB =|yB−yA|.
P❡❧♦ ❚❡♦r❡♠❛ ❞❡ P✐tá❣♦r❛s✱ t❡♠♦s✿ (AB)2
= (AC)2
+ (CB)2
⇒(AB)2
=|xB−xA|2+|yB−yA|2
∴(AB)2
= (xB−xA)2+ (yB−yA)2 ∴AB =± p
(xB−xA)2+ (yB−yA)2. ❈♦♠♦ ♦ ❝♦♠♣r✐♠❡♥t♦ ❞❡ ✉♠ s❡❣♠❡♥t♦ ♥ã♦ ♣♦❞❡ s❡r ♥❡❣❛t✐✈♦✱ t❡♠♦s q✉❡✿
AB =p(xB−xA)2+ (yB−yA)2.
■st♦ ♠♦t✐✈❛ ❛ s❡❣✉✐♥t❡ ❞❡✜♥✐çã♦✿
❉❡✜♥✐çã♦ ✷✳✶ ❆ ❞✐stâ♥❝✐❛ dAB ❡♥tr❡ ❞♦✐s ♣♦♥t♦s A = (xA, yA) ❡ B = (xB, yB) é ❞❛❞❛ ♣♦r✿
❞AB = p
(xB−xA)2+ (yB−yA)2
✷✳✸ ❉✐stâ♥❝✐❛ ❡♥tr❡ ♣♦♥t♦ ❡ r❡t❛
❱❡❥❛♠♦s ❛❣♦r❛ ♦ ❝á❧❝✉❧♦ ❞❛ ❞✐stâ♥❝✐❛ ❡♥tr❡ ✉♠ ♣♦♥t♦ P ❡ ✉♠❛ r❡t❛ r✳ ❊ss❛ ❞✐stâ♥❝✐❛ é ❞❡✜♥✐❞❛ ❛ s❡❣✉✐r✳
❙❡❥❛ P ✉♠ ♣♦♥t♦ ❡ r ✉♠❛ r❡t❛✳ ❆ ❞✐stâ♥❝✐❛ dP r✱ ❞♦ ♣♦♥t♦ P à r❡t❛ r✱ é ❛ ♠❡❞✐❞❛ ❞♦ s❡❣♠❡♥t♦ P P′✱ ♦♥❞❡ P′ é ❛ ♣r♦❥❡çã♦ ♦rt♦❣♦♥❛❧ ❞❡P s♦❜r❡ r✳
❚❡♦r❡♠❛ ✷✳✶ ❆ ❞✐stâ♥❝✐❛ d❡♥tr❡ ✉♠ ♣♦♥t♦P = (x0, y0)❡ ✉♠❛ r❡t❛r :ax+by+c= 0 é ❞❛❞❛ ♣♦r✿
✷✳✸✳ ❉■❙❚➶◆❈■❆ ❊◆❚❘❊ P❖◆❚❖ ❊ ❘❊❚❆
❞ ❂ |ax0√+by0+c|
a2+b2
❉❡♠♦♥str❛çã♦✿ Pr✐♠❡✐r♦ ❝❛s♦✿ ❈♦♥s✐❞❡r❡♠♦s ✉♠ ♣♦♥t♦P = (x0, y0) ❡ ✉♠❛ r❡t❛ r ❞❡ ❡q✉❛çã♦ ❣❡r❛❧ax+by+c= 0✱ t❛✐s q✉❡ P /∈r ❡r ♥ã♦ é ✈❡rt✐❝❛❧ ♥❡♠
❤♦r✐③♦♥t❛❧✿
❋✐❣✉r❛ ✷✳✸✿ ❉✐stâ♥❝✐❛ ❞❡ ✉♠ ♣♦♥t♦ à r❡t❛
E é ♦ ♣♦♥t♦ ❞❛ r❡t❛r ❞❡ ❛❜s❝✐ss❛ x0✳ ❙✉❜st✐t✉✐♥❞♦ x=x0 ♥❛ ❡q✉❛çã♦ r✱ t❡♠♦s✿
ax0+by+c= 0⇒y=−ax0+c
b .
▲♦❣♦✱ E =
x0,−ax0+c
b
✳
F é ♦ ♣♦♥t♦ ❞❛ r❡t❛r ❞❡ ♦r❞❡♥❛❞❛ y0✳ ❙✉❜st✐t✉✐♥❞♦y =y0 ♥❛ ❡q✉❛çã♦ ❞❡ r✱ t❡♠♦s✿
ax+by0+c= 0 ⇒x=−by0+c
a .
▲♦❣♦✱ F =
− by0a+c, y0
✳
▲❡♠❛✿ ❊♠ t♦❞♦ tr✐â♥❣✉❧♦ r❡tâ♥❣✉❧♦✱ ♦ ♣r♦❞✉t♦ ❞❛ ♠❡❞✐❞❛ ❞❛ ❤✐♣♦t❡♥✉s❛ ♣❡❧❛ ♠❡❞✐❞❛ ❞❡ s✉❛ ❛❧t✉r❛ r❡❧❛t✐✈❛ ❛ ❡ss❛ ❤✐♣♦t❡♥✉s❛ é ✐❣✉❛❧ ❛♦ ♣r♦❞✉t♦ ❞❛s ♠❡❞✐❞❛s ❞♦s
❝❛t❡t♦s✳ ❆ss✐♠ s❡♥❞♦✱ ♥♦ tr✐â♥❣✉❧♦ r❡tâ♥❣✉❧♦ P EF✱ t❡♠♦s✿
✷✳✸✳ ❉■❙❚➶◆❈■❆ ❊◆❚❘❊ P❖◆❚❖ ❊ ❘❊❚❆
EF ·d=P E·P F
⇒
s
x0+by0+c
a
2
+
y0+ax0+c
b
2
·d = s
y0+ax0+c
b
2
·
s
x0+by0 +c
a
2
⇒
r
(ax0+by0+c)2
a2 +
(by0+ax0+c)2
b2 · d =
r
(by0+ax0+c)2
b2 ·
r
(ax0+by0+c)2 a2
⇒
s
(ax0+by0+c)2
a2
+b2 a2b2
· d = r
(by0+ax0+c)2
b2 ·
r
(ax0+by0+c)2 a2
⇒ |ax0+by0+c|
√
a2+b2
|a| · |b| · d =
|by0+ax0+c|
|b| ·
|ax0+by0+c|
|a| .
❖ ♣♦♥t♦ P ♥ã♦ ♣❡rt❡♥❝❡ ❛ r❀ ❡♥tã♦ ax0+by0+c6= 0✳ ▲♦❣♦✱ t❡♠♦s √a2+b2
· d=|ax0+by0+c| ⇒ d= |ax0√+by0+c|
a2+b2 .
❙❡❣✉♥❞♦ ❝❛s♦✿ ✭❈❛s♦s ♣❛rt✐❝✉❧❛r❡s✮ ✶◦✮ P ∈r
❙❡ ♦ ♣♦♥t♦ P = (x0, y0) ♣❡rt❡♥❝❡ à r❡t❛ r:ax+by+c= 0✱ ❡♥tã♦ t❡♠♦s q✉❡ ax0+by0+c= 0 ❡ q✉❡ ❛ ❞✐stâ♥❝✐❛ ❞❡ P ❛r é ✐❣✉❛❧ ❛ ③❡r♦✳ ◆♦t❡✱ ♣♦rt❛♥t♦✱ q✉❡ ❛
❢ór♠✉❧❛ ❞❡❞✉③✐❞❛ ♥♦ ♣r✐♠❡✐r♦ ❝❛s♦ ✈❛❧❡ t❛♠❜é♠ ♣❛r❛ ❡ss❡ ❝❛s♦ ♣❛rt✐❝✉❧❛r✱ ♣♦✐s✿
d= |ax0√+by0+c|
a2+b2 =
|0|
√
a2+b2 = 0.
✷◦✮r é ✈❡rt✐❝❛❧
❙❡r é ✈❡rt✐❝❛❧✱ ❡♥tã♦ s✉❛ ❡q✉❛çã♦ ❣❡r❛❧ é ❞❛ ❢♦r♠❛ax+c= 0✱ ❝♦♠ a6= 0✳ ❆ ❞✐stâ♥❝✐❛ d é ❞❛❞❛ ♣♦r✿
d= x0+ c a =
ax0+c
a
=
|ax0+c|
|a| .
◆♦t❡ q✉❡ ❛ ❢ór♠✉❧❛ ♦❜t✐❞❛ ♥❛ ♣r✐♠❡✐r❛ ♣❛rt❡ ✈❛❧❡ t❛♠❜é♠ ♣❛r❛ ❡ss❡ ❝❛s♦✱ ♣♦✐s✿
d= |ax0√+ 0y0+c|
a2+ 02 =
|ax0+c|
|a| .
✸◦✮r é ❤♦r✐③♦♥t❛❧
❆♥❛❧♦❣❛♠❡♥t❡ ❛♦ s❡❣✉♥❞♦ ❝❛s♦✱ ♣r♦✈❛✲s❡ q✉❡ ❛ ❢ór♠✉❧❛ ♦❜t✐❞❛ ♥❛ ♣r✐♠❡✐r❛ ♣❛rt❡ ✈❛❧❡ t❛♠❜é♠ ♣❛r❛ r ❤♦r✐③♦♥t❛❧✳
✷✳✹✳ ❉❊❋■◆■➬➹❖ ❉❊ P❆❘➪❇❖▲❆
✷✳✹ ❉❡✜♥✐çã♦ ❞❡ P❛rá❜♦❧❛
❉❡✜♥✐çã♦ ✷✳✷ ❉❛❞♦ ✉♠ ♣♦♥t♦ F ❡ ✉♠❛ r❡t❛d ❞❡ ✉♠ ♣❧❛♥♦ α✱ ❝♦♠F /∈d✱ ❝❤❛♠❛✲
s❡ ♣❛rá❜♦❧❛ P ♦ ❧✉❣❛r ❣❡♦♠étr✐❝♦ ❢♦r♠❛❞♦s ♣❡❧♦s ♣♦♥t♦s ❞❡ss❡ ♣❧❛♥♦ ❡q✉✐❞✐st❛♥t❡ ❞❡ d ❡ F✳
✷✳✺ ❊❧❡♠❡♥t♦s ♣r✐♥❝✐♣❛✐s
❈♦♠ ❜❛s❡ ♥❛ ❞❡✜♥✐çã♦ ✹✳✶✱ ♦ ♣♦♥t♦ F ❡ ❛ r❡t❛ d sã♦ ♦ ❢♦❝♦ ❡ ❛ ❞✐r❡tr✐③ ❞❛
♣❛rá❜♦❧❛✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✳ ❆ r❡t❛ q✉❡ ♣❛ss❛ ♣♦r F ❡ é ♣❡r♣❡♥❞✐❝✉❧❛r à ❞✐r❡tr✐③ dé
♦ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ ✭❊✐①♦ e✮ ❞❛ ♣❛rá❜♦❧❛✳ ❖ ♣♦♥t♦ V✱ ✐♥t❡rs❡❝çã♦ ❞❛ ♣❛rá❜♦❧❛
❝♦♠ ♦ ❡✐①♦ ❞❡ s✐♠❡tr✐❛✱ é ♦ ✈ért✐❝❡ ❞❛ ♣❛rá❜♦❧❛✳ ❆ ❞✐stâ♥❝✐❛ p❞♦ ❢♦❝♦ F à ❞✐r❡tr✐③ d é ❝❤❛♠❛❞♦ ❞❡ ♣❛râ♠❡tr♦ ❞❛ ♣❛rá❜♦❧❛✳
◆♦t❡ q✉❡ ❛ ❞✐stâ♥❝✐❛ ❡♥tr❡ ♦ ✈ért✐❝❡ V ❡ ♦ ❢♦❝♦ F é ♠❡t❛❞❡ ❞♦ ♣❛râ♠❡tr♦ p✱ ♣♦✐sV
♣❡rt❡♥❝❡ à ♣❛rá❜♦❧❛ ❡✱ ♣♦rt❛♥t♦✱ V ❡q✉✐❞✐st❛ ❞❡ F ❡d✳ ❆ss✐♠✱ t❡♠♦s✿
V F =V d
V F +V d=p
⇒ ❱❋ ❂ p2 ❡ ❱❞ ❂ p2
❆❜❛✐①♦✱ t❡♠♦s ❛ ✜❣✉r❛ ❞❡ ✉♠❛ ♣❛rá❜♦❧❛ ♦❜t✐❞❛ ❛tr❛✈és ❞❛ s❡❝çã♦ tr❛♥s✈❡rs❛❧ ♥♦ ❝♦♥❡✳
✷✳✺✳ ❊▲❊▼❊◆❚❖❙ P❘■◆❈■P❆■❙
❋✐❣✉r❛ ✷✳✹✿ ❉❡✜♥✐çã♦ ❞❡ ♣❛rá❜♦❧❛
❋✐❣✉r❛ ✷✳✺✿ ❙❡❝çã♦ ❞♦ ❝♦♥❡
✷✳✻✳ ❊◗❯❆➬➹❖ ❉❆ P❆❘➪❇❖▲❆
✷✳✻ ❊q✉❛çã♦ ❞❛ ♣❛rá❜♦❧❛
❙❡❥❛♠ F = (x0, y0) ❡ d:ax+by+c= 0 ♦ ❢♦❝♦ ❡ ❛ ❞✐r❡tr✐③ ❞❡ ✉♠❛ ♣❛rá❜♦❧❛✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✳
❖❜té♠✲s❡ ✉♠❛ ❡q✉❛çã♦ ❞❡ss❛ ♣❛rá❜♦❧❛ ❝♦♥s✐❞❡r❛♥❞♦ ✉♠ ♣♦♥t♦ ❣❡♥ér✐❝♦P = (x, y) ❡ ✐♠♣♦♥❞♦ q✉❡ P F =P d✱ ♦✉ s❡❥❛✿
p
(x−x0)2+ (y
−y0)2 = |ax√+by+c|
a2+b2 .
❱❛♠♦s ♠♦str❛r ❛ s❡❣✉✐r q✉❡ t♦❞❛s ❛s ❝ô♥✐❝❛s ♥ã♦ ❞❡❣❡♥❡r❛❞❛s✱ ❝♦♠ ❡①❝❡çã♦ ❞❛ ❝✐r❝✉♥❢❡rê♥❝✐❛✱ ♣♦❞❡♠ s❡r ❞❡s❝r✐t❛s ❞❡ ✉♠❛ ♠❡s♠❛ ♠❛♥❡✐r❛✳
Pr♦♣♦s✐çã♦ ✷✳✶ ❙❡❥❛ d ✉♠❛ r❡t❛ ✜①❛ ✭❞✐r❡tr✐③✮ ❡ F ✉♠ ♣♦♥t♦ ✜①♦ ✭❢♦❝♦✮ ♥ã♦
♣❡rt❡♥❝❡♥t❡ ❛ d✳ ❖ ❝♦♥❥✉♥t♦ ❞♦s ♣♦♥t♦s ❞♦ ♣❧❛♥♦ P ❂ ✭①✱ ②✮ t❛✐s q✉❡
❞✐st✭P✱ ❋✮❂ ❡ · dist(P, d) ✭✷✳✶✮
✷✳✻✳ ❊◗❯❆➬➹❖ ❉❆ P❆❘➪❇❖▲❆
❡♠ q✉❡ e >0 é ✉♠❛ ❝♦♥st❛♥t❡ ✜①❛ ❞❡♥♦♠✐♥❛❞❛ ❡①❝❡♥tr✐❝✐❞❛❞❡ ✶✱ ✭❛✮ s❡ e= 1✱ ❡♥tã♦ ❛ ❝ô♥✐❝❛ é ✉♠❛ ♣❛rá❜♦❧❛✳
✭❜✮ s❡ 0< e <1✱ ❡♥tã♦ ❛ ❝ô♥✐❝❛ é ✉♠❛ ❡❧✐♣s❡✳ ✭❝✮ s❡ e >1✱ ❡♥tã♦ ❛ ❝ô♥✐❝❛ é ✉♠❛ ❤✐♣ér❜♦❧❡✳
❘❡❝✐♣r♦❝❛♠❡♥t❡✱ t♦❞❛ ❝ô♥✐❝❛ q✉❡ ♥ã♦ s❡❥❛ ✉♠❛ ❝✐r❝✉♥❢❡rê♥❝✐❛ ♣♦❞❡ s❡r ❞❡s❝r✐t❛ ♣♦r ✉♠❛ ❡q✉❛çã♦ ❞❛ ❢♦r♠❛ ✷✳✶✳
❉❡♠♦♥str❛çã♦✿ ❙❡ e= 1 ❛ ❡q✉❛çã♦ ✷✳✶ é ❛ ♣ró♣r✐❛ ❞❡✜♥✐çã♦ ❞❛ ♣❛rá❜♦❧❛✳ ❱❛♠♦s ❝♦♥s✐❞❡r❛r ♦ ❝❛s♦ ❡♠ q✉❡e >0✱ ❝♦♠ e6= 1✳ ❙❡❥❛ D=dist(F, d)✳ ❙❡♠ ♣❡r❞❛ ❞❡ ❣❡♥❡r❛❧✐❞❛❞❡ ♣♦❞❡♠♦s t♦♠❛r ♦ ❢♦❝♦ ❝♦♠♦ s❡♥❞♦ ♦ ♣♦♥t♦ F = (p,0)❡ ❛ ❞✐r❡tr✐③
❝♦♠♦ s❡♥❞♦ ❛ r❡t❛ ✈❡rt✐❝❛❧ d:x= p
e2✱ ❡♠ q✉❡ p=
De2
1−e2 s❡ ❛ r❡t❛ d ❡st✐✈❡r ❛
❞✐r❡✐t❛ ❞♦ ❢♦❝♦ F ✭❋✐❣✉r❛s ✹✳✻ ❡ ✹✳✼✮ ❡ p= De
2
e2
−1 s❡ ❛ r❡t❛ d ❡st✐✈❡r ❛ ❡sq✉❡r❞❛ ❞♦ ❢♦❝♦ F ✭❋✐❣✉r❛s ✹✳✽ ❡ ✹✳✾✮✳
❋✐❣✉r❛ ✹✳✻✿ ❊❧✐♣s❡✱ ✉♠ ❞♦s s❡✉s ❢♦❝♦s ❡ ❛ r❡t❛ ❞✐r❡tr✐③ à ❞✐r❡✐t❛✳
❋✐❣✉r❛ ✹✳✼✿ ❍✐♣ér❜♦❧❡✱ ✉♠ ❞♦s s❡✉s ❢♦❝♦s ❡ ❛ r❡t❛ ❞✐r❡✲ tr✐③ à ❞✐r❡✐t❛✳
✶❊①❝❡♥tr✐❝✐❞❛❞❡ é ✉♠ ♣❛râ♠❡tr♦ ❛ss♦❝✐❛❞♦ ❛ q✉❛❧q✉❡r ❝ô♥✐❝❛✱ q✉❡ ♠❡❞❡ ♦ s❡✉ ❞❡s✈✐♦ ❡♠
r❡❧❛çã♦ ❛ ✉♠❛ ❝✐r❝✉♥❢❡rê♥❝✐❛✳
✷✳✻✳ ❊◗❯❆➬➹❖ ❉❆ P❆❘➪❇❖▲❆
❋✐❣✉r❛ ✹✳✽✿ ❊❧✐♣s❡✱ ✉♠ ❞♦s s❡✉s ❢♦❝♦s ❡ ❛ r❡t❛ ❞✐r❡tr✐③ à ❡sq✉❡r❞❛✳
❋✐❣✉r❛ ✹✳✾✿ ❍✐♣ér❜♦❧❡✱ ✉♠ ❞♦s s❡✉s ❢♦❝♦s ❡ ❛ r❡t❛ ❞✐r❡✲ tr✐③ à ❡sq✉❡r❞❛✳
❆ss✐♠✱ ♦ ❝♦♥❥✉♥t♦ ❞♦s ♣♦♥t♦s P = (x, y) t❛✐s q✉❡
dist(P, F) = e·dist(P, d),
♣♦❞❡ s❡r ❡s❝r✐t♦ ❝♦♠♦ s❡♥❞♦ ♦ ❝♦♥❥✉♥t♦ ❞♦s ♣♦♥t♦s P = (x, y) t❛✐s q✉❡
p
(x−p)2+y2 = e
x−
p e2
✱
❡❧❡✈❛♥❞♦ ❛♦ q✉❛❞r❛❞♦ ❡ s✐♠♣❧✐✜❝❛♥❞♦✱ ♦❜t❡♠♦s
(1−e2
)x2
+y2
= p2
1
e2 −1
✱
q✉❡ ♣♦❞❡ ❛✐♥❞❛ s❡r ❡s❝r✐t❛ ❝♦♠♦
x2 p2 e2
+ y
2
p2
(1−e2
)
e2
✳ ✭✷✳✷✮
❙❡ 0< e < 1✱ ❡st❛ é ✉♠❛ ❡q✉❛çã♦ ❞❡ ✉♠❛ ❡❧✐♣s❡✳ ❙❡ e >1✱ é ❛ ❡q✉❛çã♦ ❞❡ ✉♠❛
❤✐♣ér❜♦❧❡✳ P❛r❛ ♠♦str❛r ❛ r❡❝í♣r♦❝❛✱ ❝♦♥s✐❞❡r❡ ✉♠❛ ❡❧✐♣s❡ ♦✉ ❤✐♣ér❜♦❧❡ ❝♦♠ ❡①❝❡♥tr✐❝✐❞❛❞❡ e >0 ❡ ✉♠ ❞♦s ❢♦❝♦s F = (p,0)✳ ➱ ❢á❝✐❧ ✈❡r✐✜❝❛r q✉❡ ✷✳✷ é ❛ ❡q✉❛çã♦ ❞❡st❛ ❝ô♥✐❝❛ ❡ ♣♦rt❛♥t♦ ✷✳✶ t❛♠❜é♠ ♦ é✱ ❝♦♠ ❛ r❡t❛ ❞✐r❡tr✐③ s❡♥❞♦
d:x= p
e2✳
✷✳✼✳ ❊◗❯❆➬Õ❊❙ ❈❆◆Ô◆■❈❆❙ ❉❆ P❆❘➪❇❖▲❆ ❈❖▼ ❱➱❘❚■❈❊ ◆❆ ❖❘■●❊▼
✷✳✼ ❊q✉❛çõ❡s ❈❛♥ô♥✐❝❛s ❞❛ ♣❛rá❜♦❧❛ ❝♦♠ ❱ért✐❝❡
♥❛ ♦r✐❣❡♠
❱❡❥❛♠♦s ❡♥tã♦ ❝♦♠♦ ❞❡t❡r♠✐♥❛r ❛s ❡q✉❛çõ❡s ❝❛♥ô♥✐❝❛s ♦✉ ❡q✉❛çõ❡s r❡❞✉③✐❞❛s ❞❛s ♣❛rá❜♦❧❛s ❡st✉❞❛♥❞♦✲❛s ❝❛s♦ ❛ ❝❛s♦✳
✶♦ ❈❛s♦✿ ❖ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ ❝♦✐♥❝✐❞❡ ❝♦♠ ♦ ❡✐①♦ ①
◆❛ ✜❣✉r❛ ❛♦ ❧❛❞♦ t❡♠✲s❡ ✉♠❛ ♣❛rá❜♦❧❛ ❝♦♠ ❝♦♥❝❛✈✐❞❛❞❡ ✈♦❧t❛❞❛ ♣❛r❛ ❛ ❞✐r❡✐t❛ r❡♣r❡s❡♥t❛❞❛ ♥♦ s✐st❡♠❛ ❝❛rt❡s✐❛♥♦ ①❖② ❡ ❝✉❥❛ ❞✐r❡tr✐③ t❡♠ ❡q✉❛çã♦ x=−p
2✳ ❚❡♠♦s t❛♠❜é♠ q✉❡✿
P = (x, y) é ✉♠ ♣♦♥t♦ ❣❡♥ér✐❝♦ ❞❛ ♣❛rá✲ ❜♦❧❛✳
F =
p
2,0
é ♦ ❢♦❝♦✳
P′ =
− p2, y
é ♦ ♣é ❞❛ ♣❡r♣❡♥❞✐❝✉❧❛r ❜❛✐①❛❞❛ ❞♦ ♣♦♥t♦ P s♦❜r❡ ❛ ❞✐r❡tr✐③✳
P♦r ❞❡✜♥✐çã♦✱ t❡♠♦s q✉❡✿
d(P, F) = d(P, P′)✱ ❞❛í
s
x− p
2 2
+ (y−0)2
= s
x+p
2 2
+ (y−y)2
❊❧❡✈❛♥❞♦ ❛♠❜♦s ♦s ♠❡♠❜r♦s ❛♦ q✉❛❞r❛❞♦✱ t❡♠♦s q✉❡✿
x2
−px+ p
2
4 +y
2
=x2
+px+p
2
4 ❉♦♥❞❡✿ y2
= 2px✱ q✉❡ r❡♣r❡s❡♥t❛ ❛ ❡q✉❛çã♦ ❝❛♥ô♥✐❝❛ ❞❛ ♣❛rá❜♦❧❛ ❝♦♠ ✈ért✐❝❡ ♥❛
♦r✐❣❡♠ ❡ ❝✉❥♦ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ é ♦ ❡✐①♦ x✳
◆❛ ❡q✉❛çã♦ y2
= 2px✱ ♣♦❞❡♠♦s t❡r ❛s s❡❣✉✐♥t❡s s✐t✉❛çõ❡s✿
✷✳✼✳ ❊◗❯❆➬Õ❊❙ ❈❆◆Ô◆■❈❆❙ ❉❆ P❆❘➪❇❖▲❆ ❈❖▼ ❱➱❘❚■❈❊ ◆❆ ❖❘■●❊▼
❙❡p > 0✱ ❛ ♣❛rá❜♦❧❛ t❡♠ ❝♦♥✲
❝❛✈✐❞❛❞❡ ✈♦❧t❛❞❛ ♣❛r❛ ❛ ❞✐✲ r❡✐t❛✱
❙❡p <0✱ ❛ ♣❛rá❜♦❧❛ t❡♠ ❝♦♥✲
❝❛✈✐❞❛❞❡ ✈♦❧t❛❞❛ ♣❛r❛ ❛ ❡s✲ q✉❡r❞❛✳
✷♦ ❈❛s♦✿ ❖ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ ❝♦✐♥❝✐❞❡ ❝♦♠ ♦ ❡✐①♦ ②
❆ ✜❣✉r❛ ❛♦ ❧❛❞♦ t❡♠✲s❡ ✉♠❛ ♣❛rá❜♦❧❛ ❝♦♠ ❝♦♥❝❛✈✐❞❛❞❡ ✈♦❧t❛❞❛ ♣❛r❛ ❝✐♠❛ r❡♣r❡s❡♥t❛❞❛ ♥♦ s✐st❡♠❛ ❝❛rt❡s✐❛♥♦ ①❖② ❡ ❝✉❥❛ ❞✐r❡tr✐③ t❡♠ ❡q✉❛çã♦ y=−p
2✳ ❚❡♠♦s t❛♠❜é♠ q✉❡✿
P = (x, y)✳
F =
0,p
2
✳
P′ =
x,−p
2
✳
✷✳✼✳ ❊◗❯❆➬Õ❊❙ ❈❆◆Ô◆■❈❆❙ ❉❆ P❆❘➪❇❖▲❆ ❈❖▼ ❱➱❘❚■❈❊ ◆❆ ❖❘■●❊▼
P♦r ❞❡✜♥✐çã♦✱ t❡♠♦s q✉❡✿
d(P, F) = d(P, P′)✱ ❞❛í
s
(x−0)2+
y− p
2 2
= s
(x−x)2+
y+ p
2 2
❊❧❡✈❛♥❞♦ ❛♠❜♦s ♦s ♠❡♠❜r♦s ❛♦ q✉❛❞r❛❞♦✱ t❡♠♦s q✉❡✿
x2
+y2
−py+p
2
4 =y
2
+py+ p
2
4 ❉♦♥❞❡✿ x2
= 2py✱ q✉❡ r❡♣r❡s❡♥t❛ ❛ ❡q✉❛çã♦ ❝❛♥ô♥✐❝❛ ❞❛ ♣❛rá❜♦❧❛ ❝♦♠ ✈ért✐❝❡ ♥❛
♦r✐❣❡♠ ❡ ❝✉❥♦ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ é ♦ ❡✐①♦ y✳
◆❛ ❡q✉❛çã♦ x2
= 2py✱ ♣♦❞❡♠♦s t❡r ❛s s❡❣✉✐♥t❡s s✐t✉❛çõ❡s✿
❙❡p >0✱ ❛ ♣❛rá❜♦❧❛ t❡♠ ❝♦♥❝❛✈✐❞❛❞❡
✈♦❧t❛❞❛ ♣❛r❛ ❝✐♠❛✳ ❙❡✈♦❧t❛❞❛ ♣❛r❛ ❜❛✐①♦✳p <0✱ ❛ ♣❛rá❜♦❧❛ t❡♠ ❝♦♥❝❛✈✐❞❛❞❡ ❊①❡♠♣❧♦ ✶✮ ❉❡t❡r♠✐♥❡ ❛ ❡q✉❛çã♦ ❞❛ ♣❛rá❜♦❧❛ ❞❡ ❢♦❝♦F = (0,−5) ❡ ❞✐r❡tr✐③
d:y= 5✳
❘❡s♦❧✉çã♦✿ ❆♦ ♠❛r❝❛r♠♦s ♥♦ ♣❧❛♥♦ ❝❛rt❡s✐❛♥♦ ♦ ❢♦❝♦ F = (0,−5) ❡ ❞✐r❡tr✐③
y= 5✱ ♣❡r❝❡❜❡♠♦s q✉❡ ♦ ✈ért✐❝❡ ❡st❛rá ♥❛ ♦r✐❣❡♠✱ ❝♦♠♦ ♠♦str❛ ❛ ✜❣✉r❛ ❛❜❛✐①♦✳
✷✳✼✳ ❊◗❯❆➬Õ❊❙ ❈❆◆Ô◆■❈❆❙ ❉❆ P❆❘➪❇❖▲❆ ❈❖▼ ❱➱❘❚■❈❊ ◆❆ ❖❘■●❊▼
❯s❛♥❞♦ ❛ ❞❡✜♥✐çã♦ ❞❡ ♣❛rá❜♦❧❛✱ t❡♠♦s✿ ❞✭P✱ ❋✮ ❂ ❞✭P✱ ❞✮
⇒ px2+ (y+ 5)2 =p(x
−x)2+ (y
−5)2
⇒ x2
+y2
+ 10y+ 25 =y2
−10y+ 25
⇒ x2
=−20y
❊①❡♠♣❧♦ ✷✮ ❉❡t❡r♠✐♥❡ ♦ ❢♦❝♦ ❡ ❛ ❞✐r❡tr✐③ ❞❛ ♣❛rá❜♦❧❛ ❞❡ ❡q✉❛çã♦y2
= 5x✳
❘❡s♦❧✉çã♦✿ ❆ ❡q✉❛çã♦ y2
= 5x é ✉♠❛ ❡q✉❛çã♦ ❞❛ ❢♦r♠❛ y2
= 2px✱ ❝♦♠ p > 0✳
❈♦♠♣❛r❛♥❞♦ ❛s ❡q✉❛çõ❡s✱ t❡♠♦s✿ 2p= 5 ⇒ p= 5
2 ⇒
p
2 = 5 4 ❉❛í✱ ❛s ❝♦♦r❞❡♥❛❞❛s ❞♦ ❢♦❝♦ sã♦ F =
5 4,0
❡ ❛ r❡t❛ ❞✐r❡tr✐③ éx=−5 4✳
✷✳✽✳ ❚❘❆◆❙▲❆➬➹❖ ❉❊ ❊■❳❖❙
✷✳✽ ❚r❛♥s❧❛çã♦ ❞❡ ❊✐①♦s
❯♠❛ ✈❡③ ❝♦♥❤❡❝✐❞❛ ❛s ❝♦♦r❞❡♥❛❞❛s ❞❡ ✉♠ ♣♦♥t♦ ♦✉ ❛ ❡q✉❛çã♦ ❞❡ ✉♠❛ ❝✉r✈❛ ❡♠ r❡❧❛çã♦ ❛ ✉♠ ❝❡rt♦ s✐st❡♠❛ ❞❡ r❡❢❡rê♥❝✐❛✱ ♣♦❞❡♠♦s ❡s❝r❡✈❡r ❛s ♥♦✈❛s ❝♦♦r❞❡♥❛❞❛s
❞❡ss❡ ♣♦♥t♦ ♦✉ ❞❛ ♥♦✈❛ ❡q✉❛çã♦ ❞❛ ❝✉r✈❛ ❡♠ r❡❧❛çã♦ ❛ ✉♠ ♥♦✈♦ s✐st❡♠❛ ❞❡ r❡❢❡rê♥❝✐❛✳ ❆ss✐♠✱ ❛ ❝✉r✈❛ ❝✉❥❛ ❡q✉❛çã♦ f(x, y) = 0 q✉❛♥❞♦ r❡❢❡r✐❞❛ ❛ ✉♠ s✐st❡♠❛
❞❡ ❝♦♦r❞❡♥❛❞❛s ❝❛rt❡s✐❛♥❛s ①❖② tr❛♥s❢♦r♠❛r✲s❡✲á ♥✉♠❛ ❡q✉❛çã♦ ❞♦ t✐♣♦
F(x′, y′) = 0✱ q✉❛♥❞♦ r❡❢❡r✐❞❛ ❛ ✉♠ ♥♦✈♦ s✐st❡♠❛ ❞❡ ❝♦♦r❞❡♥❛❞❛s ❝❛rt❡s✐❛♥❛s
①✬❖✬②✬✳
❊ss❡ ♥♦✈♦ s✐st❡♠❛ é ♦❜t✐❞♦ ❛tr❛✈és ❞❡ ✉♠❛ tr❛♥s❧❛çã♦ ❞❡ ❡✐①♦s ❡✴♦✉ ✉♠❛ r♦t❛çã♦ ❞❡ ❡✐①♦s✳ ❊♥❢❛t✐③❡✲s❡ q✉❡ ♥✉♠❛ tr❛♥s❢♦r♠❛çã♦ ❞❡ ❝♦♦r❞❡♥❛❞❛s ✭♠❡❞✐❛♥t❡ ✉♠❛ tr❛♥s❧❛çã♦ ♦✉ r♦t❛çã♦✮ ♥ã♦ é ❛❢❡t❛❞❛ ❛ ❢♦r♠❛ ❞❛ ❝✉r✈❛ ♦✉ ♦ ❣rá✜❝♦ ❞❛ ❝✉r✈❛✳ ◆♦
❡♥t❛♥t♦✱ ❤á ❛❧t❡r❛çã♦ ♥❛ ❡q✉❛çã♦ ❞❡ss❛ ❝✉r✈❛✳
◆♦ P❧❛♥♦ ❈❛rt❡s✐❛♥♦ ①❖②✱ ❝♦♥s✐❞❡r❡ ✉♠ ♣♦♥t♦ ❖✬ ❂ (x0, y0)✳ ■♥tr♦❞✉③✐♥❞♦ ✉♠
♥♦✈♦ s✐st❡♠❛ ①✬❖✬②✬ t❛❧ q✉❡ ❖✬ s❡❥❛ ❛ ♥♦✈❛ ♦r✐❣❡♠ ❡ ♦ ❡✐①♦ ❖✬①✬ t❡♥❤❛ ❛ ♠❡s♠❛ ❞✐r❡çã♦ ❡ s❡♥t✐❞♦ ❞❡ ❖① ❡ ❖✬②✬ t❡♥❤❛ ❛ ♠❡s♠❛ ❞✐r❡çã♦ ❡ s❡♥t✐❞♦ ❞❡ ❖②✳ ❉✐③❡♠♦s q✉❡ ♦ ♥♦✈♦ s✐st❡♠❛ ①✬❖✬②✬ ❢♦✐ ♦❜t✐❞♦ ♣♦r ✉♠❛ tr❛♥s❧❛çã♦ ❞♦ ❛♥t✐❣♦ s✐st❡♠❛ ①❖②✳ ❊♠ ❛♠❜♦s ♦s s✐st❡♠❛s s❡ ❝♦♥s❡r✈❛♠ ❛s ✉♥✐❞❛❞❡s ❞❡ ♠❡❞✐❞❛✳ ◆❛ ✜❣✉r❛ ❛❜❛✐①♦✱ ♣♦❞❡♠♦s ✈❡r✐✜❝❛r ♦ ♥♦✈♦ s✐st❡♠❛ ❞❡ ❝♦♦r❞❡♥❛❞❛s ❞❡♥tr♦ ❞♦ ♣❧❛♥♦
①❖②✳
❉❡ss❛ ❢♦r♠❛✱ ❛s ❝♦♦r❞❡♥❛❞❛s ❞♦ ♣♦♥t♦ P ❡♠ r❡❧❛çã♦ ❛♦s s✐st❡♠❛ ①❖② ❡ ①✬❖✬②✬ sã♦
r❡❧❛❝✐♦♥❛❞❛s ♣❡❧❛s ❢ór♠✉❧❛s✿
x=x0+x′
y=y0+y′
❱❡❥❛♠♦s ❡♥tã♦ ❝♦♠♦ ❞❡t❡r♠✐♥❛r ❛s ❢♦r♠❛s ❝❛♥ô♥✐❝❛s ❞❛s ♣❛rá❜♦❧❛s tr❛♥s❧❛❞❛❞❛s ❡st✉❞❛♥❞♦ ♦s ❝❛s♦ ♣r✐♥❝✐♣❛✐s✳
✶♦ ❈❛s♦✿ P❛rá❜♦❧❛ ❝♦♠ ✈ért✐❝❡ V = (x0, y0) ❡ r❡t❛ ❢♦❝❛❧ ♣❛r❛❧❡❧❛ ❛♦ ❡✐①♦
❖①✳
✷✳✽✳ ❚❘❆◆❙▲❆➬➹❖ ❉❊ ❊■❳❖❙
P❛r❛ ♦❜t❡r♠♦s ❛ ❢♦r♠❛ ❝❛♥ô♥✐❝❛ ❞❛ ♣❛rá❜♦❧❛ ❞❡ ✈ért✐❝❡ ♥♦ ♣♦♥t♦ V = (x0, y0)❡ r❡t❛ ❢♦❝❛❧ ♣❛r❛❧❡❧❛ ❛♦ ❡✐①♦ ❖①✱ ✈❛♠♦s ❝♦♥s✐❞❡r❛r ♦ s✐st❡♠❛ ❞❡ ❡✐①♦s ♦rt♦❣♦♥❛✐s ①✬❖✬②✬✱ ❝♦♠ ♦r✐❣❡♠ O′ =V = (x0, y0) ❡ ❡✐①♦s ❖✬①✬ ❡ ❖✬②✬ ❝♦♠ ❛ ♠❡s♠❛ ❞✐r❡çã♦ ❡
s❡♥t✐❞♦ ❞♦s ❡✐①♦s ❖① ❡ ❖②✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✳ ❙❛❜❡♠♦s q✉❡✱ ♥♦ s✐st❡♠❛ ①✬❖✬②✬✱ ❛ ❡q✉❛çã♦ ❞❛ ♣❛rá❜♦❧❛ é P ✿ y′2
= 2px′❀ ♦ ❢♦❝♦ é
F′ =
p
2,0
❀ ♦ ✈ért✐❝❡ éV′ = (0,0)❀ ❛ ❞✐r❡tr✐③ d′ :x′ =−p
2 ❡ ❛ r❡t❛ ❢♦❝❛❧ é y
′ = 0✳
❙✉❜st✐t✉✐♥❞♦✱ x = x0 +x′ ❡ y = y0 +y′✱ ♥❛
❡q✉❛çã♦ ❞❛ ♣❛rá❜♦❧❛ y′2
= 2px′✱ t❡♠♦s✿
P : (y−y0)2
= 2p(x−x0)
❖ ♣❛râ♠❡tr♦ p s❡rá ♣♦s✐t✐✈♦ ♦✉ ♥❡❣❛t✐✈♦ s❡✱
r❡s♣❡❝t✐✈❛♠❡♥t❡ ❛ ❝♦♥❝❛✈✐❞❛❞❡ ❞❛ ♣❛rá❜♦❧❛ ❡st✐✈❡r ✈♦❧t❛❞❛ ♣❛r❛ ❛ ❞✐r❡✐t❛ ♦✉ ♣❛r❛ ❛ ❡sq✉❡r❞❛✳
❊ s❡✉s ❡❧❡♠❡♥t♦s ♥❡ss❡ ❝❛s♦✱ sã♦✿
❖ ❋♦❝♦✿ F =
x0 +p
2, y0
❖ ❱ért✐❝❡✿ V = (x0, y0) ❆ ❉✐r❡tr✐③✿ d:x=x0− p
2
❆♦ ❞❡s❡♥✈♦❧✈❡r ❛ ❡q✉❛çã♦ (y−y0)2
= 2p(x−x0) ❡ ✐s♦❧❛♥❞♦ ❛ ✈❛r✐á✈❡❧ x✱ ♦❜t❡♠♦s✿
✷✳✽✳ ❚❘❆◆❙▲❆➬➹❖ ❉❊ ❊■❳❖❙
x= 1
2p |{z} a y2 − y0 p |{z} b
y+ y
2
0 + 2px0
2p
| {z } c
✭✶✮
♦✉ x=ay2
+by+c ✭✷✮
❈♦♠♣❛r❛♥❞♦ ♦s ❝♦❡✜❝✐❡♥t❡s ❞❡ ✭✶✮ ❡ ✭✷✮✱ ♦❜s❡r✈❡ q✉❡✿
a= 1
2p ⇒ ♣ ❂
1 2a
b=−y0
p ⇒ y0 =−bp ⇒ ②0 =−
b
2a
❊st❛ ú❧t✐♠❛ ❢ór♠✉❧❛ ❡♠ ❞❡st❛q✉❡ ♣❡r♠✐t❡ ❝❛❧❝✉❧❛r ❛ ♦r❞❡♥❛❞❛ ❞♦ ✈ért✐❝❡ ❞❛ ♣❛rá❜♦❧❛ ✭②0).
✷♦ ❈❛s♦✿ P❛rá❜♦❧❛ ❝♦♠ ✈ért✐❝❡ V = (x0, y0) ❡ r❡t❛ ❢♦❝❛❧ ♣❛r❛❧❡❧❛ ❛♦ ❡✐①♦
❖②✳
❈♦♠♦ ♥♦ ❝❛s♦ ❛♥t❡r✐♦r✱ ❝♦♥s✐❞❡r❛♥❞♦ ♦ s✐st❡♠❛ ❞❡ ❡✐①♦s ♦rt♦❣♦♥❛✐s ①✬❖✬②✬✱ ❝♦♠ ♦r✐❣❡♠O′ =V = (x0, y0) ❡ ❡✐①♦s ❖✬①✬ ❡ ❖✬②✬ q✉❡ tê♠ ❛ ❛ ♠❡s♠❛ ❞✐r❡çã♦ ❡ s❡♥t✐❞♦
❞♦s ❡✐①♦s ❖① ❡ ❖②✱ r❡s♣❡❝t✐✈❛♠❡♥t❡✳ ❊♥tã♦✱ ♣♦❞❡♠♦s ♦❜t❡r ❛s ❡q✉❛çõ❡s ❡ ♦s ❡❧❡♠❡♥t♦s ❞❛s ♣❛rá❜♦❧❛s ❝♦♠ ✈ért✐❝❡ V = (x0, y0) ❡ r❡t❛ ❢♦❝❛❧ ♣❛r❛❧❡❧❛ ❛♦ ❡✐①♦ ❖②✳ ❉❛ ♠❡s♠❛ ❢♦r♠❛✱ s✉❜st✐t✉✐♥❞♦x=x0+x′ ❡ y=y0 +y′✱ ♥❛ ❡q✉❛çã♦ ❞❛ ♣❛rá❜♦❧❛
x′2
= 2py′✱ t❡♠♦s✿
P : (x−x0)2
= 2p(y−y0) ✭✶✮
❆♥❛❧♦❣❛♠❡♥t❡✱ ❛ ♣❛rá❜♦❧❛ ❞❡ ❝♦♥❝❛✈✐✲ ❞❛❞❡ ✈♦❧t❛❞❛ ♣❛r❛ ❝✐♠❛ ✭q✉❛♥❞♦ p > 0✮
♦✉ ❝♦♥❝❛✈✐❞❛❞❡ ✈♦❧t❛❞❛ ♣❛r❛ ❜❛✐①♦ ✭q✉❛♥❞♦
p <0✮ t❡♠ ❛ ❢♦r♠❛✿
◆♦ ❡♥t❛♥t♦✱ ❞❡s❡♥✈♦❧✈❡♥❞♦ ✭✶✮ ❡ ✐s♦❧❛♥❞♦ ❛ ✈❛r✐á✈❡❧y✱ t❡♠♦s✿
y= 1
2p
|{z} a
x2
− x0p
|{z} b
x+ x
2
0+ 2py0
2p
| {z } c
✭✷✮
♦✉ y=ax2
+bx+c ✭✸✮
✷✳✽✳ ❚❘❆◆❙▲❆➬➹❖ ❉❊ ❊■❳❖❙
❙✐♠✐❧❛r♠❡♥t❡ ❛♦ ❝❛s♦ ❛♥t❡r✐♦r✱ ❛ ❝♦♠♣❛r❛çã♦ ❞♦s ❝♦❡✜❝✐❡♥t❡s ❞❡ ✭✷✮ ❡ ✭✸✮ ♣❡r♠✐t❡ ❝♦♥❝❧✉✐r q✉❡✿
a= 1
2p ⇒ ♣ ❂
1 2a
b =−x0
p ⇒ x0 =−bp ⇒ ①0 =−
b
2a
❊①❡♠♣❧♦✿ ❊s❜♦❝❡ ♦ ❣rá✜❝♦ ❞❛ ♣❛rá❜♦❧❛(x−1)2
=−12(y−3)✳ ❘❡s♦❧✉çã♦✿
❖❜s❡r✈❡ q✉❡ ❛ ❡q✉❛çã♦ ❞❛❞❛ é ❞❛ ❢♦r♠❛ (x−x0)2
= 2p(y−y0) P❡❧❛ ❝♦♠♣❛r❛çã♦ ❞❛s ❢ór♠✉❧❛s✱ ♣♦❞❡♠♦s ❝♦♥❝❧✉✐r q✉❡✿
✲ ♦ ✈ért✐❝❡ é ♦ ♣♦♥t♦ V = (1,3)
✲ ❛ ♣❛rá❜♦❧❛ t❡♠ ♦ ❡✐①♦ ❞❡ s✐♠❡tr✐❛ ♣❛r❛❧❡❧♦ ❛♦ ❡✐①♦ ② ✭✈❛r✐á✈❡❧ ❞♦ ✶♦ ❣r❛✉✮
✲ ❛ ❝♦♥❝❛✈✐❞❛❞❡ ❞❛ ♣❛rá❜♦❧❛ é ♣❛r❛ ❜❛✐①♦ ✭s❡❣✉♥❞♦ ♠❡♠❜r♦ ❞❛ ❡q✉❛çã♦ é ♥❡❣❛t✐✈♦✮ P♦❞❡♠♦s ❡♥tã♦ ❡s❜♦ç❛r ♦ ❣rá✜❝♦ ❞❡ss❛ ♣❛rá❜♦❧❛ ❛ ♠❡♥♦s ❞♦ s❡✉ ❢♦❝♦ ❡ ❞❡ s✉❛
❞✐r❡tr✐③✳
• ❈♦♦r❞❡♥❛❞❛s ❞♦ ❢♦❝♦✿
|2p|= 12 ⇒ |p|= 6 ⇒
p
2 = 3 ◆♦t❡ q✉❡ xF =x0 = 1
yF =y0−
p
2
= 3− |3|= 0
F = (1,0)
✷✳✾✳ ❘❖❚❆➬➹❖ ❉❊ ❊■❳❖❙
• ❊q✉❛çã♦ ❞❛ ❞✐r❡tr✐③✿
yd =y0+
p
2
= 3 +|3|= 6
d:y−6 = 0
✷✳✾ ❘♦t❛çã♦ ❞❡ ❊✐①♦s
❙❡❥❛♠ ❖① ❡ ❖② ♦s ❡✐①♦s ♣r✐♠✐t✐✈♦s✱ ❞♦ s✐st❡♠❛ ❝❛rt❡s✐❛♥♦ ♦rt♦❣♦♥❛❧ ❝♦♠ ♦r✐❣❡♠ ❡♠ ❖❂✭✵✱✵✮✳ ❙❡❥❛♠ ❖✬①✬ ❡ ❖✬②✬ ♦s ♥♦✈♦s ❡✐①♦s ❝♦♦r❞❡♥❛❞♦s ❞❡♣♦✐s q✉❡ ♦ s✐st❡♠❛ ♣r✐♠✐t✐✈♦ ❢♦✐ r♦t❛❝✐♦♥❛❞♦ ♣♦r ✉♠ â♥❣✉❧♦θ ❡♠ t♦r♥♦ ❞❛ ♦r✐❣❡♠ ❖ ≡❖✬✳ ▲♦❣♦✱ θ é ♦
â♥❣✉❧♦ ❢♦r♠❛❞♦ ❡♥tr❡ ♦s ❡✐①♦s ❖① ❡ ❖✬①✬✳ ❙❡❥❛ P = (x, y) ✉♠ ♣♦♥t♦ q✉❛❧q✉❡r ❞♦ s✐st❡♠❛ ♣r✐♠✐t✐✈♦✳ P♦rt❛♥t♦✱ ♦ ♠❡s♠♦ ♣♦♥t♦ P t❡rá ❝♦♦r❞❡♥❛❞❛s P = (x′, y′)✱ ❡♠
r❡❧❛çã♦ ❛♦ ♥♦✈♦ s✐st❡♠❛✳ P❡❧❛ ✜❣✉r❛ ❛❝✐♠❛✱ t❡♠♦s✿
x=OM −N M
y= N Q+QP
◆♦ tr✐â♥❣✉❧♦ ❖▼❘✱ t❡♠♦s✿ M R=N Q✱
❝♦sθ = OM
x′ ⇒ OM =x
′· ❝♦sθ✱
✷✳✾✳ ❘❖❚❆➬➹❖ ❉❊ ❊■❳❖❙
❋✐❣✉r❛ ✷✳✻✿ ❘♦t❛çã♦ ❞♦s ❡✐①♦s ❝♦♦r❞❡♥❛❞♦s✳
s❡♥ θ = M R
x′ ⇒ M R= N Q =x
′· s❡♥ θ✳
◆♦ tr✐â♥❣✉❧♦ P◗❘✱ t❡♠♦s✿ QR=N M✱
s❡♥ θ = QR
y′ ⇒ QR =N M =y
′· s❡♥ θ✱
❝♦sθ = QP
y′ ⇒ QP =y
′· ❝♦s θ✳
P♦rt❛♥t♦✱
x=OM −N M
y= N Q+QP ⇒
x= x′·❝♦s θ−y′· s❡♥ θ
y= x′· s❡♥ θ+y′· ❝♦sθ
❆ss✐♠✱ ❛♣ós ✉♠❛ r♦t❛çã♦ ❞❡ ✉♠ â♥❣✉❧♦θ ✭♣♦s✐t✐✈♦✱ ❛ ♣❛rt✐r ❞♦ ❡✐①♦ x ♥♦ s❡♥t✐❞♦
❛♥t✐✲❤♦rár✐♦✮ t❡♠♦s ❛s ❡q✉❛çõ❡s q✉❡ r❡❧❛❝✐♦♥❛♠ q✉❛❧q✉❡r ♣♦♥t♦P = (x, y)❞❡ ❝♦♦r❞❡♥❛❞❛s ♥♦ s✐st❡♠❛ xOy ❝♦♠ s✉❛s ❝♦♦r❞❡♥❛❞❛s ♥♦ s✐st❡♠❛x′O′y′✳ ❈❤❛♠❛❞❛s
❡q✉❛çõ❡s ❞❡ r♦t❛çã♦ R2✳
x= x′· ❝♦sθ−y′· s❡♥ θ
y= x′·s❡♥ θ+y′· ❝♦s θ ou, equivalente,
x′ = x· ❝♦s θ+y· s❡♥ θ
y′ = −x· s❡♥ θ+y· ❝♦sθ
❊ss❛s ❡q✉❛çõ❡s ♣♦❞❡♠ t❛♠❜é♠ s❡r❡♠ ❡s❝r✐t❛s ♥❛ ❢♦r♠❛ ♠❛tr✐❝✐❛❧ ❛❜❛✐①♦✿
x y
=
cosθ −senθ
senθ cosθ
·
x′
y′
♦♥❞❡
Mθ =
cosθ −senθ
senθ cosθ
é ❝❤❛♠❛❞❛ ♠❛tr✐③ ❞❡ r♦t❛çã♦ ❞❡ ✉♠ â♥❣✉❧♦ θ✱ q✉❡ r❡♣r❡s❡♥t❛ ❛ ♠❛tr✐③ ❞❡