Question

Which of the following is/are quadratic surds?

• A. $\sqrt[2]{23}$
• B. $\sqrt[3]{36}$
• C. $\sqrt[4]{49}$
• D. $\sqrt[5]{520}$

Answer 1

Answer: (A), (C)

The correct options are
A $\sqrt[2]{23}$
C $\sqrt[4]{49}$

Quadratic surds are the surds whose order is '2'
First is quadratic as it has order '2'
Second and fourth are not '2'
Third can be solved as
$\sqrt[4]{49}$ = $\sqrt[4]{43^2}$ =$\sqrt[2]{23}$ which has order 2
and hence it becomes quadratic surd
So, $\sqrt[2]{23}$ and $\sqrt[4]{49}$ are quadratic surds