Question

sin^4 theta +2sin^2 theta •cos^2 = 1 - cos^4 theta​

Answer 1

sin^4 theta + 2sin^2theta*cos^2theta+cos^4theta =1

we know that

(a+b)^2=a^2+b^2+2ab

it is written like that only

(sin^2+cos^2)^=1

we know that sin^2theta +cos^2theta=1

1^2=1

hence LHS=RHS.