How do you evaluate $sec^-1(-2)$ ?

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Answer 1 · 2017-07-11T13:37:34

$sec^(-1)(-2)=(2pi)/3$

From definition of inverse ratio if $secx=-2$ , $sec^(-1)(-2)=x$ and range is $[0,pi}$

We know that secant function is negative in $Q2$

as $sec(pi/3)=2$ , we have $sec(pi-pi/3)=sec((2pi)/3)=-2$

Hence $sec^(-1)(-2)=(2pi)/3$

How do you evaluate sec^-1(-2)sec^-1(-2)?