If f(r)=7rcosz9z2dz\displaystyle {f{{\left({r}\right)}}}={\int_{{7}}^{{\sqrt{{{r}}}}}}\frac{{{\cos{{z}}}^{{9}}}}{{{z}^{{2}}}}{\left.{d}{z}\right.} then
f(r)\displaystyle {f}'{\left({r}\right)} =