in a right angle triangle with one of the angle 0 vertify that sin square theta + cos square theta = 1
verify that sin square theta + cos square theta = 1
or
verify that: sin^2 θ + cos^2 θ = 1
construct a right-angled triangle with hypotenuse 1, a base of x and a height of y
label the base angle θ
we know that cosθ = x/1 = x
and sin θ = y/1
then sin^2 θ + cos^ θ = x^2 + y^2
but by Pythagoras, x^2 + y^2 = 1^2
so sin^2 θ + cos^ θ = 1