If p cos^2(x)+sin^2(x)=r,express cos^2(x) n terms of p and r only?

1 Answer
Mar 21, 2018

cos^2x=(r-1)/(p-1)

Explanation:

Given:
pcos^2x+sin^2x=r

cos^2x=f(p,r)

sin^2x=1-cos^2x

pcos^2x+1-cos^2x=r

1+(p-1)cos^2x=r

(p-1)cos^2x=r-1

cos^2x=(r-1)/(p-1)