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

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Answer 1 · 2018-03-21T15:02:28

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

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

$cos^2x=f(p,r)$

$sin^2x=1-cos^2x$

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

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

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

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