Function Arithmetic: Adding, Subtracting, Multiplying, and Dividing Functions

In the realm of mathematics, functions play a pivotal role, representing relationships between variables. Function arithmetic extends the concept of arithmetic operations to functions themselves. This allows us to combine and manipulate functions to create new and more complex ones. In this exploration, we’ll delve into the fundamental operations of addition, subtraction, multiplication, and division applied to functions, providing a solid foundation for understanding advanced mathematical concepts.

Adding Functions

Adding functions is as straightforward as adding numbers. To add two functions, f(x) and g(x), we simply add their corresponding outputs for each input value x. The resulting function, denoted as (f + g)(x), is defined by the following:

(f + g)(x) = f(x) + g(x)

Example:

Let f(x) = x² + 1 and g(x) = 2x – 3. Find (f + g)(x).

(f + g)(x) = f(x) + g(x) = (x² + 1) + (2x – 3)

Simplifying, we get:

(f + g)(x) = x² + 2x – 2

Subtracting Functions

Subtracting functions follows a similar logic to adding functions. To subtract g(x) from f(x), we subtract the output of g(x) from the output of f(x) for each input value x. The resulting function, denoted as (f – g)(x), is defined by:

(f – g)(x) = f(x) – g(x)

Example:

Let f(x) = 3x + 2 and g(x) = x – 1. Find (f – g)(x).

(f – g)(x) = f(x) – g(x) = (3x + 2) – (x – 1)

Simplifying, we get:

(f – g)(x) = 2x + 3

Multiplying Functions

Multiplying functions involves multiplying the outputs of the two functions for each input value x. The resulting function, denoted as (f * g)(x), is defined by:

(f * g)(x) = f(x) * g(x)

Example:

Let f(x) = x + 4 and g(x) = x – 2. Find (f * g)(x).

(f * g)(x) = f(x) * g(x) = (x + 4) * (x – 2)

Expanding the product, we get:

(f * g)(x) = x² + 2x – 8

Dividing Functions

Dividing functions involves dividing the output of f(x) by the output of g(x) for each input value x, provided that g(x) is not equal to zero. The resulting function, denoted as (f / g)(x), is defined by:

(f / g)(x) = f(x) / g(x), where g(x) ≠ 0

Example:

Let f(x) = 2x² + 1 and g(x) = x – 1. Find (f / g)(x).

(f / g)(x) = f(x) / g(x) = (2x² + 1) / (x – 1), where x ≠ 1

Note that we must exclude x = 1 from the domain of the function (f / g)(x) because it would result in division by zero, which is undefined.

Conclusion

Function arithmetic provides a powerful tool for manipulating and combining functions. Understanding these operations is crucial for solving complex mathematical problems and exploring advanced concepts in calculus and other areas of mathematics. By mastering the basics of function arithmetic, you’ll gain a deeper understanding of the relationships between functions and their applications in various fields.