Suppose it is known that the graph of the following function y = ax^3 + bx^2 + cx + d passes through four given points (xi, yi) where i=1,2,3,4 

Write a user defined function that accepts these four points as input and computes the coefficients a,b,c,d. The function should solve four linear equations in terms of the four unknowns a,b,c,d.