登录
1. 计算：
(1)$\sqrt{169×196}=$
(1)$\sqrt{169×196}=$
182
. (2)$\sqrt{4^{2}×3}=$$4\sqrt{3}$
. (3)$\sqrt{3^{2}×5^{2}}=$15
.答案
1. (1)182 (2)$4\sqrt{3}$ (3)15
2. (1)$\sqrt{\dfrac{9}{25}}=$
$\frac{3}{5}$
. (2)$\sqrt{\dfrac{2}{9}}=$$\frac{\sqrt{2}}{3}$
.答案
2. (1)$\frac{3}{5}$ (2)$\frac{\sqrt{2}}{3}$
3. (1)$\sqrt{40}=$
(4)$\sqrt{\dfrac{5}{8}}=$
$2\sqrt{10}$
. (2)$\sqrt{0.001}=$$\frac{1}{100}\sqrt{10}$
. (3)$\sqrt{(-18)×(-24)}=$$12\sqrt{3}$
.(4)$\sqrt{\dfrac{5}{8}}=$
$\frac{1}{4}\sqrt{10}$
. (5)$\sqrt{1\dfrac{1}{2}}=$$\frac{1}{2}\sqrt{6}$
.答案
3. (1)$2\sqrt{10}$ (2)$\frac{1}{100}\sqrt{10}$ (3)$12\sqrt{3}$ (4)$\frac{1}{4}\sqrt{10}$ (5)$\frac{1}{2}\sqrt{6}$
4. 下列运算正确的是 (
A.$\sqrt{5^{2}-4^{2}}=\sqrt{5^{2}}-\sqrt{4^{2}}=5-4=1$
B.$\sqrt{(-16)×(-25)}=\sqrt{-16}×\sqrt{-25}=-4×(-5)=20$
C.$\sqrt{(\dfrac{5}{13})^{2}+(\dfrac{12}{13})^{2}}=\dfrac{5}{13}+\dfrac{12}{13}=\dfrac{17}{13}$
D.$\sqrt{4^{2}×7}=\sqrt{4^{2}}×\sqrt{7}=4\sqrt{7}$
D
)A.$\sqrt{5^{2}-4^{2}}=\sqrt{5^{2}}-\sqrt{4^{2}}=5-4=1$
B.$\sqrt{(-16)×(-25)}=\sqrt{-16}×\sqrt{-25}=-4×(-5)=20$
C.$\sqrt{(\dfrac{5}{13})^{2}+(\dfrac{12}{13})^{2}}=\dfrac{5}{13}+\dfrac{12}{13}=\dfrac{17}{13}$
D.$\sqrt{4^{2}×7}=\sqrt{4^{2}}×\sqrt{7}=4\sqrt{7}$
答案
4. D
5. 下列化简错误的是 (
A.$\sqrt{\dfrac{5}{9}}=\dfrac{\sqrt{5}}{\sqrt{9}}=\dfrac{\sqrt{5}}{3}$
B.$\sqrt{0.01×0.49}=\sqrt{0.01}×\sqrt{0.49}=0.07$
C.$\sqrt{1\dfrac{1}{49}}=\sqrt{1}×\sqrt{\dfrac{1}{49}}=1×\dfrac{1}{7}$
D.$\sqrt{\dfrac{2}{7}}=\dfrac{\sqrt{2}}{\sqrt{7}}=\dfrac{1}{7}\sqrt{14}$
C
)A.$\sqrt{\dfrac{5}{9}}=\dfrac{\sqrt{5}}{\sqrt{9}}=\dfrac{\sqrt{5}}{3}$
B.$\sqrt{0.01×0.49}=\sqrt{0.01}×\sqrt{0.49}=0.07$
C.$\sqrt{1\dfrac{1}{49}}=\sqrt{1}×\sqrt{\dfrac{1}{49}}=1×\dfrac{1}{7}$
D.$\sqrt{\dfrac{2}{7}}=\dfrac{\sqrt{2}}{\sqrt{7}}=\dfrac{1}{7}\sqrt{14}$
答案
5. C
6. 使等式$\sqrt{x(x-2)}=\sqrt{x}·\sqrt{x-2}$成立的$x$的取值范围是 (
A.$x≥2$
B.$x≥0$
C.$x＞2$
D.$x≠2$
A
)A.$x≥2$
B.$x≥0$
C.$x＞2$
D.$x≠2$
答案
6. A
