Question

Convert each equation from rectangular to polar form. (x + 2)2 + ( y − 2)2 = 8

Answer 1

Making the usual substitutions (x=r·cos(θ), y=r·sin(θ)), you have
  (r·cos(θ))² +4r·cos(θ) +4 + (r·sin(θ))² -4r·sin(θ) +4 = 8
  r(r +4·cos(θ) -4·sin(θ)) = 0
Dividing by r then subtracting the non-r terms gives
  r = 4(sin(θ) -cos(θ))