Question

is the derivative function of:
f(x)= sqrt[4]{x} cosx

help please...

Answer 1

Please write it claerly. Is the Sqrt is common?

Answer 2

question is not clear!

Answer 3

\[f(x)= \sqrt[4]{x} cosx\]

Answer 4

use chain rule
\[ f'(x) = \frac{d (x \cos (x))^{1/4}}{d (x \cos (x))} \times { d (x\cos (x)) \over dx}\]

Answer 5

http://www.wolframalpha.com/input/?i=differentiate+%28x+cos+x%29^%281%2F4%29

Answer 6

apply te product rule
\[\left(gh\right)^\prime=gh^\prime+g^\prime h\]

\[f(x)=\sqrt[4]x\cos x=x^{1/4}\cos x\]
\[=-x^{1/4}\sin x+\frac 14x^{-3/4}\cos x\]
\[=-\sqrt[4]x\sin x+\frac {\cos x}{4x^{3/4}}\]