Question

sin^2(-theta) + cos^2(-theta) = 1
Establish the identity.

Answer 1

if a be the base, b the opposite side and c the hypotenuse
sin t = b/c
cos t= a/c
sin^2t + cos^2t= (a^2 + b^2 ) /c^2
by pythagoras thm
a^2 + b^2 = c^2
hence proved

Answer 2

Thanks man!