A Random Variable X Has a Cumulative Distribution Function F(x) $\frac { 1 } { ( x + 1 ) ^ { 2 } }$

Short Answer

A random variable X has a cumulative distribution function F(x) = 1 - $\frac { 1 } { ( x + 1 ) ^ { 2 } }$ for $$x \geq 0$$ . Find $$\operatorname { Pr } ( 1 \leq X \leq 4 )$$ .
Enter just a reduced fraction.