Question 936571
{{{x=Rcos(theta)}}}
{{{y=Rsin(theta)}}}
.
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{{{x^2+y^2=1}}}
{{{r^2cos^2(theta)+r^2sin^2(theta)=1}}}
{{{r^2(cos^2(theta)+sin^2(theta))=1}}}
{{{r^2(1)=1}}}
{{{r^2=1}}}