Total number of terms in $(x+a)^{n}-(x-a)^{n}$ $=\begin{cases}\frac{n+1}{2} & \text { if } n \text { is odd } \\ \frac{n}{2} & \text { if } n \text { is even }\end{cases}$ $\therefore$ Total number of terms in the expansion of $(x+a)^{47}-(x-a)^{47}=\frac{47+1}{2} [\because n$ is odd $]$ $=\frac{48}{2} $ $=24 $
The binomial theorem formula is used in the expansion of any power of a binomial in the form of a series. The binomial theorem formula is
Properties of Binomial Theorem
The number of coefficients in the binomial expansion of (x + y)n is equal to (n + 1).
There are (n+1) terms in the expansion of (x+y)n.
The first and the last terms are xn and yn respectively.
From the beginning of the expansion, the powers of x, decrease from n up to 0, and the powers of a, increase from 0 up to n.
The binomial coefficients in the expansion are arranged in an array, which is called Pascal's triangle. This pattern developed is summed up by the binomial theorem formula.