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Given{:[r=cos(20)","quad theta=(pi)/(4)],[x=r cos theta","quad y=r sin theta],[x=cos(2theta)cos theta","quad y=cos(2theta)sin theta]:}Now,{:[" Now, "{:[(dx)/(d theta)=(d)/(d theta)[cos(2theta)cos theta]],[=cos 2theta(d)/(d theta)cos theta+cos theta(d)/(d theta)cos 2theta],[=cos 2theta(-sin theta)+cos theta(-2sin 2theta)],[(dx)/(d theta)=-sin theta cos 2theta-2sin 2theta cos theta]:}],[{:[(dy)/(d theta)=(d)/(d theta)[sin theta cos 2theta]],[=sin theta(d)/(d theta)cos 2theta+cos 2theta(d)/(d theta)sin theta],[=sin theta(-2sin 2theta)+cos 2theta cos theta ... See the full answer