Let x ~ n (0.1) be a random variable and find the probability density of y = 4-x ^ 2

Let x ~ n (0.1) be a random variable and find the probability density of y = 4-x ^ 2

FX (x) is the density function of F (x)
FY (y) = 2fx (radical (4-y)) | DX / dy | = FX (radical (4-y)) / radical (4-y)