(Y2:5) Polar coordinates

What are x and y in polar

X=r × cosθ

Y=r × sinθ

What are r² and θ

r² = x²+y²

θ=arctan(y/x)

What shape is r=a

A circle with centre O and radius a

What shape is θ=α

A half line (0 to infinity) through O and making a angle α with the horizontal

What shape does r=αθ form

A spiral starting from O

Formula for area of a polar sector

½ ∫(β,α) (r²)dθ. Where β,α are the limiting lines

How to find tangent to parallel and perpendicular

Parallel dy/dθ =0

Perpendicular dx/dθ =0