sin^4a+2 cos a sin a- cos^4a / 2 cos^2a -1

Question

sin^4a+2 cos a sin a- cos^4a / 2 cos^2a -1

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Answer 1

(sin(a)^4+2*cos(a)*sin(a) - cos(a)^4) / (2*cos(a)^2 - 1)=tg(2 a)-1
ставь tg(2 a)-1