`(dy)/(dx)` ज्ञात कीजिए|
`x=cos theta-cos 2 theta, y=sin theta-sin 2 theta`

Explanation

`x = cos theta- cos 2 theta`
`rArr" "(dx)/(d theta)=-sin theta+2 sin 2 theta= 2 sin 2 theta- sin theta`
`y=sin theta- sin 2 theta`
`rArr" "(dy)/(d theta)=cos theta-2 cos 2 theta`
`therefore" "(dy)/(dx)=(dy//d theta)/(dx//d theta)=(cos theta-2 cos 2 theta)/(2 sin 2 theta- sin theta)`