How do you evaluate $cos^-1(cos(-(pi)/10))$ ?

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Answer 1 · 2016-07-20T12:07:27

$-pi/10$

$cos^(-1)cos(-pi/10)$ is the mathematical form for the expression

"the angle for which the cosine is cosine of $(-pi/10)$ "

So, its value is $-pi/10$ .

How do you evaluate cos^-1(cos(-(pi)/10))cos^-1(cos(-(pi)/10))?