cos^2 theta + sin^2 theta = 1?

Question

is it the same as sin^2 theta + cos^2 theta =1? which is one of phytagorean theorem?

i'm confused, please help !

Answer 1

cos^2x + sin^2x = sin^2x + cos^2x = 1 is a phytagorean theorem

  a^2 + b^2 = c^2

if x = 30 degree

sin 30 = 1/2 and cos30 = sqrt(3/2)

sin^2(30) + cos^2(30) = (1/2)^2 +( ( sqrt3)/2)^2 = 1/4 + 3/4 + 1