How do you simplify (sin60)2+(cos60)2?

1 Answer
May 25, 2015

(sin60o)2+(cos60o)2=1

In fact, for any angle θ we have sin2θ+cos2θ=1

We can see this geometrically for positive angles less than 90o (e.g. 60o) by considering a right angled triangle with angles θ, 90oθ and 90o and hypotenuse of length 1.

By the definitions of sinθ and cosθ, the side opposite the angle θ will be of length sinθ and the side adjacent to the angle θ, opposite the 90oθ angle will be of length cosθ.