Question

rút gọn \(\sqrt{\left(\sqrt{5}-3\right)}^2+\sqrt{\left(\sqrt{5}-2\right)^2}\)

+) tính:

a) \(\sqrt{8,1.250}\)

b)\(\sqrt{\dfrac{10.4,9}{16}}\)

c) \(\sqrt{8}.\sqrt{50}\)

d) \(\dfrac{\sqrt{128}}{\sqrt{18}}\)

Answer 1

Rút gọn :

\(\sqrt{\left(\sqrt{5}-3\right)^2}+\sqrt{\left(\sqrt{5}-2\right)^2}=\left|\sqrt{5}-3\right|+\left|\sqrt{5}-2\right|=\sqrt{5}-3+\sqrt{5}-2=2\sqrt{5}-5\)

Tính :

a) \(\sqrt{8,1.250}=\sqrt{81.25}=\sqrt{81}.\sqrt{25}=9.5=45\)

b) \(\sqrt{\dfrac{10.4,9}{16}}=\sqrt{\dfrac{1.49}{16}}=\dfrac{\sqrt{1}.\sqrt{49}}{\sqrt{16}}=\dfrac{7}{4}\)

c) \(\sqrt{8}.\sqrt{50}=\sqrt{8.50}=20\)

d) \(\dfrac{\sqrt{128}}{\sqrt{18}}=\sqrt{\dfrac{128}{18}}\approx2,7\)

Answer 2

\(\sqrt{\left(\sqrt{5}-3\right)^2}+\sqrt{\left(\sqrt{5}-2\right)^2}\\ =\left|\sqrt{5}-3\right|+\left|\sqrt{5}-2\right|\\ =3-\sqrt{5}+\sqrt{5}-2=1\)