How do you find the limit of $phisecphi$ as $phi->pi$ ?

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Answer 1 · 2016-12-12T11:50:13

$lim_(phi->pi) phi sec phi = -pi$

$phi sec phi = phi/cos phi$

The function is continuous in $phi = pi$ , so that:

$lim_(phi->pi) phi sec phi = pi sec(pi) = pi/cos(pi) = -pi$

How do you find the limit of phisecphiphisecphi as phi->piphi->pi?