Chapter 2.6, Problem 53E

Continuity and limits with transcendental functions Determine the interval(s) on which the following functions are continuous; then analyze the given limits.

53. $f(x)=\frac{1+\sin x}{\cos x};\underset{x\to \pi /2^{-}}{\lim }f(x);\underset{x\to 4\pi /3}{\lim }f(x)$