Q. If $(a,a^{2})$ falls inside the angle made by the lines $y = \frac{x}{2},\ x > 0$ and $y = 3x,x > 0,$ then $a$ belongs to

A) $(3,\ \infty)$
B) $\left( \frac{1}{2},\ 3 \right)$
C) $\left( - 3,\ - \frac{1}{2} \right)$
D) $\left( 0,\frac{1}{2} \right)$
Explanation

(b)
The graph of equations $x - 2y = 0\ and\ 3x - y = 0$ is as shown in the figure. Since, given point $(a,\ a^{2})$ lies in the shaded region.
[image:10_image2.emf]
$Then,\ a^{2} - \frac{a}{2} > 0$
$and\ a^{2} - 3a < 0$
$\Rightarrow \ a \in ( - \infty,\ 0) \cup \left( \frac{1}{2},\ \infty \right)$
$and\ a \in (0,\ 3)$
$\Rightarrow \ a \in \left( \frac{1}{2},\ 3 \right)$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.