Trigonometry help??

Question

 Eliminate the parameter of y=5 cos(θ) and x=5 sin(θ)

Answer 1

If x = 5cosθ  and y = 5sinθ, then x² + y² = 25cos²θ + 25sin²θ

 

                                                             = 25(cos²θ + sin²θ) = 25

 

So, x² + y² = 25