Question

Tìm Max của:

B= \(\sqrt{x^2-8x+17}+\sqrt{x^2+16}\)

Answer 1

\(B=\sqrt{\left(x-4\right)^2+1}+\sqrt{x^2+4^2}\) \(\ge\sqrt{\left(4-x+x\right)^2+\left(1+4\right)^2}=\sqrt{41}\)  

" = " \(\Leftrightarrow x=\dfrac{16}{5}\)