`(dy)/(dx)` ज्ञात कीजिए|
`x=a(theta-sin theta), y=a(1+cos theta)`

Explanation

`x=a(theta- sin theta)`
`rArr" "(dx)/(d theta)=a(1-cos theta)=2a sin^(2).(theta)/(2)`
`y=a(1+cos theta)`
`rArr" "(dy)/(d theta)=- a sin theta=-2a sin.(theta)/(2)cos.(theta)/(2)`
`therefore" "(dy)/(dx)=(dy/ d theta)/(dx/d theta)-(2asin.(theta)/(2)cos.(theta)/(2))/(2a sin^(2).(theta)/(2))=-cot.(theta)/(2)`