## Calculus, 10th Edition (Anton)

$1$
Since the limit as theta approaches zero is $\frac{0}{0}$, L'Hopital's Rule can be used. The derivative of the numerator and denominator is performed, leaving $$\lim\limits_{\theta \to 0}sec^{2} \theta=sec^{2}(0)=1^{2}=\boxed{1}.$$