Question

Find the equation of tangent to the circle x² + y² – 2ax = 0 at the point (a(1 + cosα), a sinα).

Answer 1

Equation of tangent of x² + y² – 2ax = 0 at (a(1 + cosα), asinα) is

ax(1 + cosα) + aysinα – a(x + a(1 + cosα)) = 0

ax + axcosα + aysinα – ax – a² (1 + cosα) = 0

axcosα + aysinα = a² (1 + cosα)

xcosα + ysinα = a(1 + cosα)