Question

f(x)=x^2+16/x+4√x-3 f(4)=?

Answer 1

$F(x)=x^2+ frac{16}{x} +4 sqrt{x} -3 \ \ f(x)=F`(x)=(x^2+ frac{16}{x} +4 sqrt{x} -3)`= \ \ =2x-frac{16}{x^2}+4cdot frac{1}{2 sqrt{x} } =2x-frac{16}{x^2}+frac{2}{ sqrt{x} } \ \ f(4)=2cdot 4-frac{16}{4^2}+frac{2}{ sqrt{4} }=8-1+1=8$