Question

How do you evaluate $\sec \left(\mathrm{\pi }\right)$?

Answer 1

Finding the required value:

Since, $\mathrm{\pi }=180°$, $\sec \left(\mathrm{\theta }\right)=\frac{1}{\cos \left(\mathrm{\theta }\right)}$

$\sec \left(\mathrm{\pi }\right)=\sec (180°)$

$\sec \left(\mathrm{\pi }\right)=\frac{1}{\cos (180°)}$

$\sec \left(\mathrm{\pi }\right)=\frac{1}{-1}$ $\left[\because \cos (180°)=-1\right]$

$\sec \left(\mathrm{\pi }\right)=-1$

Hence, the value of $\sec \left(\mathrm{\pi }\right)$ is$-1$.