Q. If square root of $- 7 + 24i$ is $x + iy$, then $x$ is
A) $\pm 1$
B) $\pm 2$
C) $\pm 3$
D) $\pm 4$
Explanation
(c)
Given, $x + iy = \sqrt{- 7 + 24i}$
$\therefore\ \ \ \ x = \pm \sqrt{\frac{1}{2}\lbrack( - 7)^{2} + (24)^{2} - 7\rbrack}$
$= \pm \sqrt{\frac{1}{2}\lbrack 49 + 576 - 7\rbrack}$
$= \pm \sqrt{\frac{1}{2}\lbrack 25 - 7\rbrack} = \pm \sqrt{9} = \pm 3$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.