Multinomial Expansion

when we want to find the expansion powers of the multinomial (x1 + x2 + ... + xl)^n where l>=1, as well as the coefficients.

the function gives the powers in order for possible outcomes.
e.g
(a+b+c)^3=a^3+b^3+c^3+3*a^2*b+3*a^2*c+3*b^2*a+3*b^2*c+3*c^2*a+3*c^2*b+6*a*b*c

using the function, we type
normSize=3;
normPower=3;
[powI coefI]=multiNomial(normPower,normSize);