# Arctangent online calculator

@QED arctangent calculator calculates the arctan of given numbers in degrees and radians as follows.

The atan word works as a command to calculate the arctan values and it can take several arguments separated by spaces. In the above example, the calculator calculates the arctangent of -1, 0, 25. The results are in degrees and radians.

Let's input atan and numbers in the above form!

x arctan(x)
-1 -45°
0
1 45°

## Arctangent formulas

$\textnormal{arctan}(-x) = -\textnormal{arctan}(x)$

$\textnormal{sin}(\textnormal{arctan}(x)) = \dfrac{x}{\sqrt{1 + x^2}}$

$\textnormal{cos}(\textnormal{arctan}(x)) = \dfrac{1}{\sqrt{1 + x^2}}$

$\textnormal{tan}(\textnormal{arctan}(x)) = x$

\textnormal{arctan}\left(\dfrac{1}{x}\right) = \left\{ \begin{aligned} & \dfrac{\pi}{2} - \textnormal{arctan}(x) && (x>0) \\~\\ & -\dfrac{\pi}{2} - \textnormal{arctan}(x) && (x<0) \end{aligned} \right.