Question

M= (1/1-căn a - 1/1+căn a ) × (1/ căn a -1)

A) rút gọn M

 

Answer 1

đk : x >= 0 ; x khác 1

\(M=\left(\dfrac{1}{1-\sqrt{a}}-\dfrac{1}{\sqrt{a}+1}\right)\left(\dfrac{1}{\sqrt{a}-1}\right)\)

\(=\dfrac{\sqrt{a}+1-1+\sqrt{a}}{1-a}\left(\dfrac{1}{\sqrt{a}-1}\right)=\dfrac{2\sqrt{a}}{\left(1-a\right)\left(\sqrt{a}-1\right)}\)