What is the Cartesian form of r^2+theta = -tan^2theta+4sec^2theta r2+θ=tan2θ+4sec2θ?

1 Answer
Jun 25, 2018

We know that cartesian to polar coordinates is made by

x=rcosthetax=rcosθ
y=rsinthetay=rsinθ

From these , we have then r^2=x^2+y^2r2=x2+y2 and theta=arctan(y/x)θ=arctan(yx) and y/x=tanthetayx=tanθ and sectheta=r/x=sqrt(x^2+y^2)/xsecθ=rx=x2+y2x

r^2+theta=-tan^2theta+4sec^2thetar2+θ=tan2θ+4sec2θ

x^2+y^2+arctan(y/x)=-y^2/x^2+4(x^2+y^2)/x^2x2+y2+arctan(yx)=y2x2+4x2+y2x2