If $\displaystyle {f{{\left({x}\right)}}}={{\sin}^{{{3}}}{x}}$, find $\displaystyle {f}'{\left({x}\right)}$ and then compute $\displaystyle {f}'{\left(\frac{{{5}\pi}}{{6}}\right)}$. Use exact values.

$\displaystyle {f}'{\left({x}\right)}=$   Preview Question 6 Part 1 of 2  

$\displaystyle {f}'{\left(\frac{{{5}\pi}}{{6}}\right)}=$   Preview Question 6 Part 2 of 2