Question

Evaluate
\[
\lim_{x \to (\pi/2)^-}\: cos(x)sec(5x)
\]

Answer 1

\[\lim_{x\to\pi/2^-}\frac{\cos x}{\cos5x}=\frac{0}{0}\]
Apply L'Hopital's rule, if you know it.

Answer 2

Does the - in the limit affect the answer? I get 1/5

Answer 3

http://www.wolframalpha.com/input/?i=limit+of+cos+x+sec+5x+as+x+goes+to+%28pi%2F2%29%5E-