Question 1132564
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<pre>
{{{x^2 + y^2}}} = {{{18^2*(cos^2(t) + sin^2(t))}}} ,  


{{{x^2 + y^2}}} = {{{18^2}}}


This figure is the circle of the radius 18 centered at the origin of the coordinate system.
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Answered, solved, explained and completed.