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.

=

= b× 2sinθ × cosθ (using the chain rule = 2sinθ× = 2sinθ × cosθ )

= 2bsinθcosθ . ………..(1)

= a × (2cosθ)× (-sinθ ) (using chain rule = 2cosθ× = 2 cosθ × (-sinθ ) )

= -2asinθcosθ.

Dividing (1) and (2), we get

=

= .