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

Derivatives of Trig Functions

3. Techniques of Differentiation / Derivatives of Trig Functions / Problema 1

Problema 1

Evaluate $f^{'} (x)$ at $x = \frac{π}{4}$ if $f (x) = \cos x$ .

$\frac{1}{2}$

$\frac{\sqrt{3}}{2}$

$\frac{\sqrt{2}}{2}$

$- \frac{\sqrt{2}}{2}$