How do you convert $r = 2cosθ$ into rectangular form?

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Answer 1 · 2018-03-12T07:48:38

$x^2-2x+y^2=0$

$(x-1)^2+y^2=1$

Multiply both sides by $r$ to get $r^2=2rcostheta$

$r^2=x^2+y^2$
$2rcostheta=2x$

$x^2+y^2=2x$

$x^2-2x+y^2=0$

$(x-1)^2+y^2=1$

How do you convert r = 2cosθr = 2cosθ into rectangular form?