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

Sep 12, 2017

see below

Explanation:

Use the formulas ${r}^{2} = {x}^{2} + {y}^{2} , \tan \theta = \frac{y}{x}$

${r}^{=} \sqrt{{2}^{2} + {\left(- 1\right)}^{2}} = \sqrt{5}$

$\tan \theta = - \frac{1}{2}$

$\theta = {\tan}^{-} 1 \left(- \frac{1}{2}\right) \approx - 0.46 + \pi n$

So one possible solution is $\left(\sqrt{5} , - 0.46\right) \mathmr{and} \left(2.24 , - 0.46\right)$