Find , when

Theorem: y and x are given in a different variable that is θ . We can find by finding and and then dividing them to get the required thing.

=

= a(cosθ - (-θ sinθ + cosθ )) {by using product rule, while differentiating θcosθ }

= a(θsinθ ) ………..(1)

= a(-sinθ +θ cosθ +sinθ ) {by using product rule, while differentiating θcosθ }

= a× θcosθ ……….(2)

Dividing (1) and (2), we get

=

= tanθ ANS