The function is given to be:
[tex]f(x)=2\arccos x[/tex]
We can rewrite the function using y:
[tex]y=2\arccos x[/tex]
To find the inverse, replace y with x and vice-versa:
[tex]x=2\arccos y[/tex]
Lastly, we solve for y:
[tex]\begin{gathered} \arccos y=\frac{x}{2} \\ \therefore \\ y=\frac{1}{\arccos}(\frac{x}{2}) \\ But:\cos x=\frac{1}{\arccos x} \\ Hence: \\ y=\cos(\frac{x}{2}) \end{gathered}[/tex]
Therefore, the correct option is the SECOND OPTION:
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