How do you evaluate $arcsin(-1)$ without a calculator?

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Answer 1 · 2016-11-23T13:44:53

$arcsin(-1)=-pi/2$

$arcsinx$ means the angle whose sine ratio is $x$ i.e. $theta$ where $sintheta=x$ .

Hence, $arcsin(-1)$ means the angle whose sine ratio is $-1$ .

As $sin(-pi/2)=-1$

$arcsin(-1)=-pi/2$

How do you evaluate arcsin(-1)arcsin(-1) without a calculator?