Let the probability density function of a random variable, $X$, be given as:
$f_{x}(x)=\frac{3}{2}e^{-3x}u(x)+ae^{4x}u(-x)$
where u(x) is the unit step function.
Then the value of 'a' and prob $\left\{X \leq 0\right\}$, respectively are
- $2, \frac{1}{2}$
- $4, \frac{1}{2}$
- $2, \frac{1}{4}$
- $4, \frac{1}{4}$