Gievn the expression
(x+y)^4
We will expand this using binomial expansion:
Note that in binomial expansion, as the power of x is decreasing, that of y will be decreasing
(x+y)^4 = x^4y^0 + x^3y^1 + x^2y^2 + x^1y^3 + x^0y^4
(x+y)^4 = x^4 + x^3y + x^2y^2 + xy^3 + y^4
Next is input the coefficient according to pascal triangle. Since the degree of the expression is 4, the coefficient for each term will be 1, 4, 6, 4, 1
Fix in the coefficient:
(x+y)^4 = 1x^4 + 4x^3y + 6x^2y^2 + 4xy^3 + 1y^4
(x+y)^4 = x^4 + 4x^3y + 6x^2y^2 + 4xy^3 + y^4
From the expansion, the coefficient of x^2y^2 is 6