Question

Transform the cartesian equation X²+y² = 2ax into polar equation.  

Answer 1

Putting x = rcosθ and y = r sinθ in equation we get,

 r²cos² θ+ r² sin²θ = 2ar cosθ 

or  r²(sin²θ + cos²θ) = 2ar cosθ      ( .: sin²θ + cos² θ = 1) 

or  r = 2a cosθ is the required equation in polar form.