Question #3acab
1 Answer
May 14, 2017
Explanation:
using right triangle with a vertex at the origin and angle
θ, with sides corresponding to θ
adjacent =x, opposite =y, hypotenuse =r
⇒sinθ=yr,cosθ=xr and r2=x2+y2
⇒1−sin2θ=1−y2r2=r2r2−y2r2
⇒1−sin2θ=r2−y2r2=x2r2=cos2θ