#### Answer

The Derivative is:
$\frac{ds}{dt}=2t-\sec t\tan t$

#### Work Step by Step

$s=t^2-\sec t+1$
Applying Derivative rules:
$\frac{ds}{dt}=\frac{d}{dt}(t^2)-\frac{d}{dt}(\sec t)+\frac{d}{dt}(1)$
$\frac{ds}{dt}=(2)t^{2-1}-(\sec t\tan t)+(0)$
$\frac{ds}{dt}=2t-\sec t\tan t$