inner product of functions

• 函数的内积

inner product of functions的用法和样例：

例句

1. For this reason the inner product is called also the scalar product.
   为此，内积也叫做纯量积。
2. There are many different types of abstract space in mathematics, for examples, vector space, inner product space, etc.
   数学上存在各种不同的抽象空间，例如向量空间，内积空间等。