posted by steve on .
which term in the expansion of (1/(3x^2)-x)^15 is the constant term?
The constant term is the term where the power of x in the product (1/(3x²))^r*x^(15-r) is zero, i.e.
In general, a polynomial in x is written in descending order of the power of x.
So the powers of x for the expansion are:
x^0*(x^(-2))^15 = x^(-30)
x^10*(x^(-2))^5 = x^0
x^12*(x^(-2))^3 = x^6
x^13*(x^(-2))^2 = x^9
x^14*(x^(-2))^1 = x^12
x^15*(x^(-2))^0 = x^15
Can you figure out which term gives the constant term?