Problem: Find probabilities from the pdf

Problem

$X$ is a continuous random variable with probability density function $f\left( x \right)=3x^2$ for $0≤x≤1$ ( $f\left( x \right)=0$ otherwise).

1. Find $P(X<1/2)$
2. Find $F(1/2)$
3. Find $P(X>1/2)$