\(C=\sqrt{3-2}-\sqrt{\left(1-\sqrt{2}\right)^2}=1-\left|1-\sqrt{2}\right|=1-\left(\sqrt{2}-1\right)=2-\sqrt{2}\)
Chú ý câu C đề là \(\sqrt{\left(3-\sqrt{2}^2\right)}\) , không phải \(\sqrt{\left(3-\sqrt{2}\right)^2}\) , không biết do lỗi hay cố tình
\(D=\sqrt{4^2}+\sqrt{\left(\sqrt{5}-3\right)^2}=4+\left|\sqrt{5}-3\right|=4+3-\sqrt{5}=7-\sqrt{5}\)
\(E=\left(3+\dfrac{\sqrt{5}\left(\sqrt{5}-1\right)}{\sqrt{5}-1}\right)\left(3-\dfrac{\left(\sqrt{5}+1\right)\left(5+\sqrt{5}\right)}{\left(\sqrt{5}-1\right)\left(\sqrt{5}+1\right)}\right)\)
\(=\left(3+\sqrt{5}\right)\left(3-\dfrac{5+3\sqrt{5}}{2}\right)=\left(3+\sqrt{5}\right)\left(\dfrac{1-3\sqrt{5}}{2}\right)=-6-4\sqrt{5}\)
c) Ta có: \(C=\sqrt{\left(3-\sqrt{2}\right)^2}-\sqrt{\left(1-\sqrt{2}\right)^2}\)
\(=3-\sqrt{2}-\sqrt{2}+1\)
\(=4-2\sqrt{2}\)
