If f(x)=2xt3dt\displaystyle {f{{\left({x}\right)}}}={\int_{{{2}}}^{{x}}}{t}^{{3}}{\left.{d}{t}\right.}

then
f(x)=\displaystyle {f}'{\left({x}\right)}=  
f(5)=\displaystyle {f}'{\left(-{5}\right)}=