Question

Write the parametric equations of the circle: 

x² + y² = 9

Answer 1

The equation of the circle is x² + y² = 9.

Comparing this equation with x² + y² = r²,

we get, r² =9

∴ r = 3

∴ the parametric equations are

x = r cosθ, y = r sinθ

i.e., x = 3 cosθ, y = 3 sinθ.