Which of the following is NOT equal to the square of an integer:

[Gmat_mission]

Which of the following is NOT equal to the square of an integer:

A. \(\sqrt{\sqrt{1}}\)

B. \(\sqrt4\)

C. \(\dfrac{18}2\)

D. \(41 - 25\)

E. \(36\)

Answer: B

Source: Official Guide

[Brent@GMATPrepNow]

Which of the following is NOT equal to the square of an integer:

A. \(\sqrt{\sqrt{1}}\)

B. \(\sqrt4\)

C. \(\dfrac{18}2\)

D. \(41 - 25\)

E. \(36\)

Answer: B
Although every positive number has two square roots, the square root notation (√) tells us to take only the positive root
So, for example, 9 has two square roots (3 and-3), since 3² = 9 and (-3)² = 9
However, the square root notation tells us to take the positive root, which means √9 = 3

Likewise, √1 = 1 (only)

Cheers,
Brent
Source: Official Guide