5a) Change of Variable Let be a monotone differentiable function and let . The change of variable formula for densities says that the density of is given by See Section 16.2.1 for the derivation, and notice how the derivation depends on the cdf of . The cdf was also the principal function you used to create the transformations in Parts 3 and 4 of the lab. Each time you use the change of variable formula, the main steps to find the density are: Find the possible values of . Find the inverse of . Find the derivative of . Divide the density of by the derivative of (if the derivative is negative, use its absolute value instead). Evaluate this quotient at the inverse of . Use the formula to find the density of the area of a disc that has radius . That is, find the density of . Start by constructing a SymPy expression g defined by . SymPy recognizes pi as . Remember that you already declared x and f_X(x) at the start of this part of the lab