$$\lim_{x \to \frac{\pi}{2}^-} \frac{1}{\cos^{2}{\left(x \right)}} = \infty$$
More at x→pi/2 from the left$$\lim_{x \to \frac{\pi}{2}^+} \frac{1}{\cos^{2}{\left(x \right)}} = \infty$$
$$\lim_{x \to \infty} \frac{1}{\cos^{2}{\left(x \right)}} = \left\langle 0, \infty\right\rangle$$
More at x→oo$$\lim_{x \to 0^-} \frac{1}{\cos^{2}{\left(x \right)}} = 1$$
More at x→0 from the left$$\lim_{x \to 0^+} \frac{1}{\cos^{2}{\left(x \right)}} = 1$$
More at x→0 from the right$$\lim_{x \to 1^-} \frac{1}{\cos^{2}{\left(x \right)}} = \frac{1}{\cos^{2}{\left(1 \right)}}$$
More at x→1 from the left$$\lim_{x \to 1^+} \frac{1}{\cos^{2}{\left(x \right)}} = \frac{1}{\cos^{2}{\left(1 \right)}}$$
More at x→1 from the right$$\lim_{x \to -\infty} \frac{1}{\cos^{2}{\left(x \right)}} = \left\langle 0, \infty\right\rangle$$
More at x→-oo