Question

Tính

a) -√-6²

b) -√-25/-16

c) √- -9/25

d) (-√7) ²

e) -(√3/4) ²

f) √-(2) ⁴

So sánh

√8-1 và 2

√3 và√16/2

 

Answer 1

Tính :\(a,\)\(-\sqrt{\left(-6\right)^2}=-|-6|=-6\)

\(b,\)\(-\sqrt{\frac{-25}{-16}}=-\sqrt{\left(\frac{5}{4}\right)^2}=-|\frac{5}{4}|=-\frac{5}{4}\)

\(c,\)\(\sqrt{-\frac{-9}{25}}=\sqrt{\frac{9}{25}}=\sqrt{\left(\frac{3}{5}\right)^2}=|\frac{3}{5}|=\frac{3}{5}\)

\(d,\)\(\left(-\sqrt{7}\right)^2=7\)

\(e,\)\(-\left(\frac{\sqrt{3}}{4}\right)^2=-\frac{\sqrt{3}^2}{4^2}=-\frac{3}{16}\)

\(f,\)\(\sqrt{\left(-2\right)^4}=\sqrt{\left[\left(-2\right)^2\right]^2}=|-2^2|=4\)

So sánh :\(a,\) \(\sqrt{8}-1\)

\(2=3-1=\sqrt{9}-1\)

\(\Rightarrow\sqrt{8}-1< 2\)

\(b,\)\(\sqrt{\frac{16}{2}}=\sqrt{8}>\sqrt{3}\)

\(\Rightarrow\sqrt{\frac{16}{2}}>\sqrt{3}\)