i need your help. cartesian to polar conversion..
\[r^2 \sin^2 \theta = \frac{ r^3\cos^3 \theta }{ 2a - r costheta }\]
the real equation was y^2 = x^3 / 2a - x
and i need to derive the answer which is r= 2a sin theta tan theta
Okay first left side: \[ r^2\sin^2\theta = (r\sin\theta)^2=y^2 \]
There are four formula to remember: \[ r^2=x^2+y^2\\ \theta = \tan \frac yx\\ x=r\cos\theta\\ y=r\sin\theta\\ \]
y^2 = x^3 / 2a - x.. i just substituted the rcos theta and rsin theta hehe :)
okay so square root both sides if you want \(y=f(x)\)
then...
the answer of this is r= 2a sin theta tan theta :) i need the process.. im always lost..
Wait... you started in Cartesian and are going to polar?
yes
\[ \begin{split} y^2 &= \frac{x^3}{2a - x}\\ 2ay^2-xy^2&=x^3\\ 2ay^2&=x^3+xy^2\\ 2ay^2&=x(x^2+y^2)\\ 2ar^2\sin^2\theta &=r^3\cos\theta \\ 2a\sin^2\theta &=r\cos\theta \\ r&=2a\tan\theta\sin\theta \end{split} \]
another equation.. y^2 = x(x-a)^2/ 2a- x..
the answer is r^2 - 2arsec theta + a^2 = 0.. i dont know how to derive sec
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