Question

How to determine the polar coordinate: (1,-2)?

Answer 1

`(sqrt5, -63.435°)`

Explanation:

Given (1, -2) -> (r, `theta)`

`r= sqrt(x^2+y^2)`
`theta= arctan(y/x)`

`r= sqrt(1^2+(-2)^2)=sqrt5`
`theta= arctan(-2/1)=-71.565°`

Thus polar coordinates: `(sqrt5, -63.435°)`