How do you evaluate ${cos}^{- 1} (cos (\frac{11 π}{10}))$ $cos^-1(cos((11pi)/10))$ ?

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Answer 1 · 2016-07-13T04:28:47

The operand $\frac{11 π}{10}$ $(11pi)/10$ .

If $y = f (x), x = f^{- 1} (y) . f f^{- 1} y = y and f^{- 1} f (x) = x$ $y = f(x), x =f^(-1)(y). f f^(-1)y = y and f^(-1)f(x)=x$ ,

Here, $f = cos, f^{- 1} = {cos}^{- 1} and x = \frac{11 π}{10}$ $f = cos, f^(-1)=cos^(-1) and x=(11pi)/10$

So, ${cos}^{- 1} cos (\frac{11 π}{10})$ $cos^(-1)cos ((11pi)/10)$ retiurns the operand $\frac{11 π}{10}$ $(11pi)/10$ .'

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How do you evaluate cos−1(cos(11π10))cos^-1(cos((11pi)/10))?