Câu 1:
$y'=[(\sqrt{x}+1)(\frac{1}{\sqrt{x}}-1)]' $
$y'=(\sqrt{x}+1)'(\frac{1}{\sqrt{x}}-1) + (\sqrt{x}+1)(\frac{1}{\sqrt{x}}-1)' $
$y'=(\frac{1}{2\sqrt{x}})(\frac{1}{\sqrt{x}}-1) + (\sqrt{x}+1)(-\frac{(\sqrt{x})'}{x})$
$y'=(\frac{1}{2\sqrt{x}})(\frac{1}{\sqrt{x}}-1) + (\sqrt{x}+1)(-\frac{1}{2x\sqrt{x}})$