Question

So sánh các số :

\(\left(\frac{1}{2}\right)^1;\left(\frac{1}{3}\right)^{-1};\left(\frac{1}{2}\right)^2;\left(\frac{1}{4}\right)^{-1};\left(\frac{1}{3}\right)^{-2}\)

Answer 1

Cho mk sửa xíu : ( 1/2)^-1 ; (1/2)^-2

Answer 2

(1/2)^-1=2

(1/2)^-2=4

có 2<4

=>(1/2)^-1<(1/2)^-2

Answer 3

Ta có :

 \(\left(\frac{1}{2}\right)^{-1}=\left(2^{-1}\right)^{-1}=2\)

\(\left(\frac{1}{3}\right)^{-1}=3\)

\(\left(\frac{1}{2}\right)^{-2}=\left(2^{-1}\right)^{-2}=2^2=4\)

\(\left(\frac{1}{4}\right)^{-1}=\left(4^{-1}\right)^{-1}=4\)

\(\left(\frac{1}{3}\right)^{-2}=\left(3^{-1}\right)^{-2}=3^2=9\)

Do đó ta có :

\(\left(\frac{1}{2}\right)^{-1}< \left(\frac{1}{3}\right)^{-1}< \left(\frac{1}{2}\right)^{-2}=\left(\frac{1}{4}\right)^{-1}< \left(\frac{1}{3}\right)^{-2}\)