Answer
$m=-0.500$
Work Step by Step
We are given that we have solutions at $\alpha=(m+1/2)\pi$.
Isolating the equation for $m$, we obtain:
$m=\alpha/\pi-1/2$
Now we can use the alpha found in part 17b ($\alpha$=0) to find the associated $m$ value//////////;
$m=0/\pi-1/2$
$m=-0.500$
