$\operatorname{atan}{\left(- \frac{1}{2} \right)}$

$\operatorname{atan}{\left(- \frac{1}{2} \right)} = - \operatorname{atan}{\left(\frac{1}{2} \right)}\approx -0.463647609000806$A

$\operatorname{atan}{\left(- \frac{1}{2} \right)} = -\left(\frac{180 \operatorname{atan}{\left(\frac{1}{2} \right)}}{\pi}\right)^{\circ}\approx -26.565051177077989^{\circ}$A

For graph, see the graphing calculator.