Prove:sin ^2(7π/8)+sin^2(5π/8)+sin^2(3π/8)+sin^2(π/8)=0

2 answers

If you read AND FOLLOW the directions on the Post a New Question screen, you'll get better results.

School Subject: ________ (Examples: math, science, algebra, geography)
Since sin(π-x) = sin(x),

sin 7π/8 = sin π/8
sin 5π/8 = sin 3π/8

But your equation is clearly false, since all those sin^2 are positive, so they cannot add to zero.