Letſ be the function satisfying S'(x)=-3xf(x), for all real numbers x, with f(1) = 4 and lim f(x)=0. (a) Evaluate "-3xf(x) dx . Show the work that leads to your answer (b) Use Euler's method, starting at x = 1 with a step size of 0.5, to approximate $(2). --3xy with the initial (e) Write an expression for y= y(x) by solving the differential equation condition S(1) - 4.