evaluate-fxfprimeleftxright-at-x4xfracpi4-if-fxcosxfleftxrightcos-x

Question

Evaluate f′$$(x)f^{\prime}$$\left(x\right) at x=π4x=\frac{\pi}{4} if f(x)=cos⁡xf\left(x\right)=\cos x.

Accepted Answer

−22-\frac{\sqrt2}{2}

Answer

12\frac12

Answer

32\frac{\sqrt3}{2}

Answer

22\frac{\sqrt2}{2}

Evaluate f′(x)f^{\(\prime\)}\(\left\)(x\(\right\)) at x=π4x=\(\frac{\pi}{4}\) if f(x)=cosxf\(\left\)(x\(\right\))=\(\cos\) x.