I have the parametric function(adsbygoogle = window.adsbygoogle || []).push({}); x(t) = (1-t^2)/(1+t^2), y(t) = 2t/(1+t^2)and need to eliminate the parameter and find a Cartesian equation.

I've tried to substitute t = tan u, then x(t) = cos(2u) and y(t) = tan(2u). From that I get y = sin(2x)/x. However, when I entered the original parametric function into a grapher, I get an entirely different graph. Where did I go wrong?

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# Homework Help: Eliminating the parameter

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