Answer
$-2$
Work Step by Step
RECALL:
(1) $\sec{\theta}=\frac{1}{\cos{\theta}}$
(2) $\csc{\theta} = \frac{1}{\sin{\theta}}$
With $\sin{\frac{\pi}{2}}=1$ and $\cos{\pi}=-1$, then
$\sec\pi -csc{\frac {\pi }{2}}
\\=\dfrac {1}{\cos \pi }-\dfrac {1}{\sin{\frac {\pi }{2}}}
\\=\dfrac {1}{-1}-\dfrac {1}{1}
\\=-1-1
\\=-2$
