Topic: Exponents and Polynomials
Subtopic: Negative Exponents
Overview
Throughout the course we have been working with positive exponents, but in this lesson we formalize the processes and rules. We also add to our repertoire negative exponents (like 2-4 and x-3) and powers of zero (like 30 and -y0). Negative powers mean to take a reciprocal (flip), so for example: x-3 means 1/x3, (2x)-4=1/(2x)4=1/(16x4), 2x-4=2/x4, and (2/x)-4=(x/2)4=x4/16.
Caution: Notice how important the parentheses are? They indicate exactly what is to the power and what isn't. Careful!
Scientific notation is a specific way of writing numbers and involves positive/negative powers. It allows us to easily deal with very large (and very small) numbers without having to write out and keep track of dozens of zeros. Scientific notation opens up a world of applications especially in the physical sciences!
Objectives
By the end of this topic you should know and be prepared to be tested on:
- 6.1.1 Understand the effect of a zero or negative power on a number or variable
- 6.1.2 Simplify expressions containing integer exponents (positive, negative, and zero)
- 6.1.3 Use the rules of exponents (product rule, power rule, and quotient rule) accurately
- 6.1.4 Algebraically convert numbers in decimal form into scientific notation and numbers in scientific notation into decimal form
- 6.1.5 Perform operations with numbers in scientific notation both algebraically and electronically
Terminology
Define: zero power, negative power, product rule of exponents, power rules of exponents, quotient rule of exponents (memorize all three rules!), decimal form (of a number)r, scientific notation
Text Notes
Text:
Intro & Inter Algebra for CS 3ed by Blitzer, sect. 5.7
- Review section 5.2 which covers the basic rules of positive exponents and section 5.5 which covers zero exponents before covering negative exponents in section 5.7.
- The many rules of exponents displayed in purple boxes throughout 5.7 are worth memorizing!
- This section includes scientific notation which is important to be able to compute manually and electronically.