Question

How do you convert `(2,-1)` into polar form?

Answer 1

see below

Explanation:

Use the formulas `r^2=x^2+y^2, tan theta=y/x`

`r^=sqrt(2^2+(-1)^2)=sqrt5`

`tan theta =-1/2`

`theta = tan^-1 (-1/2) ~~-0.46+pin`

So one possible solution is `(sqrt 5, -0.46) or (2.24,-0.46)`