Question

What is the polar form of `(-5,13)`?

Answer 1

`( sqrt194 , 1.94 )`

Explanation:

Using the formulae that links Cartesian and Polar coordinates.

`• x^2 + y^2 = r^2`

`• x = rcostheta`

`• y = rsintheta`

`• theta = tan^-1 (y/x )`

`r^2 = (-5)^2 + 13^2 = 194 rArr r = sqrt194`

`theta = tan^-1(13/-5) = - 1.2`

(- 5 , 13 ) is in 2nd quadrant and so `theta = pi - 1.2 = 1.94`