Question

[Buddy]

Cho \(\alpha ,\beta \) là hai số thực với \(\alpha  < \beta \). Khẳng định nào sau đây đúng?

A. \({\left( {0,3} \right)^\alpha } < {\left( {0,3} \right)^\beta }\).                 

B. \({\pi ^\alpha } \ge {\pi ^\beta }\).                                

C. \({\left( {\sqrt 2 } \right)^\alpha } < {\left( {\sqrt 2 } \right)^\beta }\).    

D. \({\left( {\frac{1}{2}} \right)^\beta } > {\left( {\frac{1}{2}} \right)^\alpha }\).

Answer 1

[HT.Phong (9A5)]

Ta có: 

A. \(\alpha< \beta\)

\(\Rightarrow\left(0,3\right)^{\alpha}>\left(0,3\right)^{\beta}\)

Sai 

B. \(\alpha< \beta\)

\(\Rightarrow\pi^{\alpha}< \pi^{\beta}\)

Sai

C. \(\alpha< \beta\)

\(\Rightarrow\left(\sqrt{2}\right)^{\alpha}< \left(\sqrt{2}\right)^{\beta}\)

Đúng

D. \(\alpha< \beta\)

\(\Rightarrow\left(\dfrac{1}{2}\right)^{\alpha}>\left(\dfrac{1}{2}\right)^{\beta}\)

Sai 

⇒ Chọn C