[tex]\bf \textit{what is the sine of }90^o?\qquad 1\textit{ then what is the }sin^{-1}(1)?\quad 90^o
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\textit{now then, what is }sin(~~sin^{-1}(1)~~)?\textit{ is just }1\\\\
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[tex]\bf likewise\qquad
\begin{cases}
cos(~~cos^{-1}(whatever)~~)\implies whatever\\
sin(~~sin^{-1}(whatever)~~)\implies whatever\\
tan(~~tan^{-1}(whatever)~~)\implies whatever\\
cot(~~cot^{-1}(whatever)~~)\implies whatever\\
sec(~~sec^{-1}(whatever)~~)\implies whatever\\
csc(~~csc^{-1}(whatever)~~)\implies whatever
\end{cases}[/tex]
so, surely you know what that is then.
