Question

How do you evaluate `cos^-1(cos((11pi)/10))`?

Answer 1

The operand `(11pi)/10`.

Explanation:

If `y = f(x), x =f^(-1)(y). f f^(-1)y = y and f^(-1)f(x)=x`,

Here, `f = cos, f^(-1)=cos^(-1) and x=(11pi)/10`

So, `cos^(-1)cos ((11pi)/10)` retiurns the operand `(11pi)/10`.'

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