If cos A+cos2A=1, then sin2A + sin4A=1


True

Given: cos A+cos2 A = 1


(Rearranging, and taking cos2 A on the right side of equation)


cos A = 1- cos2 A


( sin2 θ+cos2 θ = 1 sin2 θ = 1- cos2 θ)


cos A = sin2 A …eq. 1


Squaring both sides,


we get cos2 A = sin4 A …eq. 2


We have to find sin2A+sin4 A=1


So, adding eq. 1 and eq. 2, we get


sin2A + sin4 A= cos A + cos2 A (As given)


sin2A+ sin4 A = 1


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