# Function Algebra

Function arithmetic and algebra deals with manipulating functions using the usual arithmetic of numbers. You may recall that arithmetic operations on numbers include sum, difference, multiplication, division and exponentiation. A particularly important computation required in calculus is that of the **difference quotient of a function** (also known by **slope of a line, average rate of change, **etc.) over an interval. In addition to these operations, we also learn about **composition **of two or more functions in a later section.

The result of arithmetic operations on functions is again a function. So naturally we would be particularly interested in the domain of the resulting function which in turn depends on the individual functions.

**Learning Objectives:**

- Function arithmetic - Sum, Difference, Product, and Quotient
- Composition of Functions
- Domain of Resulting Function
- Difference Quotient for polynomials, rational functions and n
^{th}-root functions. - Examples of functions in practice -
- Position function of a projectile
- Compound Interest
- Volume of Regular objects (cylinder, cone, sphere)

Price-Demand, Revenue Cost, Average Cost and Profit function