Let $f ( x ) = \frac { 2 c } { \left( 1 + x ^ { 2 } \right) }$

Short Answer

Let $f ( x ) = \frac { 2 c } { \left( 1 + x ^ { 2 } \right) }$
a) For what value of $c$ is $f$ a probability density function?
b) For that value of $c$ , find $P ( - 1 < X < 1 )$ .