Question

Rút gọn: \(\dfrac{2}{\sqrt{3}-1}-\dfrac{2}{\sqrt{3}+1}\)

Answer 1

\(\dfrac{2}{\sqrt{3}-1}-\dfrac{2}{\sqrt{3}+1}=\dfrac{2\sqrt{3}+2-2\sqrt{3}+2}{\left(\sqrt{3}^2\right)-1}=\dfrac{4}{2}=2\)

Answer 2

=\(\dfrac{2\left(\sqrt{3}+1\right)-2\left(\sqrt{3}-1\right)}{\left(\sqrt{3}+1\right)\left(\sqrt{3}-1\right)}\)=\(\dfrac{2\sqrt{3}+2-2\sqrt{3}+2}{\left(\sqrt{3}\right)^2-1^2}\)=\(\dfrac{4}{8}\)=\(\dfrac{1}{2}\)

xong rồi nha :)

Answer 3

ôi xin lỗi tớ làm sai rồi

Answer 4

\(\dfrac{2}{\sqrt{3}-1}-\dfrac{2}{\sqrt{3}+1}=\dfrac{2\left(\sqrt{3}+1\right)-2\left(\sqrt{3}-1\right)}{2}=\dfrac{2\left(\sqrt{3}+1-\sqrt{3}+1\right)}{2}=\dfrac{2.2}{2}=2\)