Question

Given $A\times B=2$. Find the minimum value of (A + B), where A and B are positive.

• A. $3\sqrt{2}$
• B. $4\sqrt{2}$
• C. $\sqrt{2}$
• D. $2\sqrt{2}$

Answer 1

The correct option is D $2\sqrt{2}$

We know that, when the product of two numbers is constant, their sum is minimum when the numbers are equal.
$\therefore$ A = B
$\Rightarrow A^2=2\Rightarrow A=\sqrt{2}\therefore (A+B{)}_{min}=\sqrt{2}+\sqrt{2}=2\sqrt{2}$