Cos^2 65градусов+sin^2 115градусов

Question

Cos^2 65градусов+sin^2 115градусов

Answer 1

= cos^2 65 + sin^2 65 = 1

Comments

sin^2 115градусов?

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формула приведения sin(180 - ф) = sin ф

Answer 2

Cos ^{2} 65+ sin ^{2}115=cos ^{2} 65+sin ^{2}(180-65)=cos ^{2} 65+sin ^{2}65=1