Sin4A - cos4A = sin2A - cos2A

Question

Can i just square root the left side??:O

Answer 1

I don't think it is an identity.
let A=90 deg
sin(360)-cos(360)=0-1

sin(180)-cos(180)=0+1

The sides are not equal.

Answer 2

?? Im sorry i don't understand what u did but im sure that this is an identity we have to prove that the left side equals the right side:)