Coefficient of a Particular Power in a Product

Coefficient of a Particular Power in a Product

## Formula

For:

$$(a+bx)^m(c+dx)^n$$

the coefficient of $$x^r$$ is:

$$\sum_{k=0}^{r}{}^mC_k a^{m-k}b^k{}^nC_{r-k}c^{n-r+k}d^{r-k}$$

## Usage

- Used to find the coefficient of a particular power when two binomial expressions are multiplied.