Let x ~ n (0,1), y = x & # 178;, find the probability density of Y

Let x ~ n (0,1), y = x & # 178;, find the probability density of Y

The probability density function of X: F_ X(x)=1/√(2π)·e^(-x^2/2)
When y ≤ 0, f_ Y(y)=P{Y