1. Lesson 4

1.4. Explore 3

Mathematics 30-2 Module 7

Module 7: Exponents and Logarithms

 

In Try This 3 you may have determined that the a-value affected the end behaviour. When a is positive, the graph is increasing. The graph starts in quadrant IV and ends in quadrant I. When a is negative, the graph is decreasing. The graph starts in quadrant I and ends in quadrant IV.

 

 

This shows two graphs of y equals a times the base 10 logarithm of x. The variable a is positive in one graph and negative in the other.

 

The other characteristics of the graph do not depend on the sign of a, as shown in the following table:

 

Characteristics a < 0 a > 0
Value of x-intercept 1 1
Value of y-intercept none none
Domain x > 0 x > 0
Range y ∈ R y ∈ R
End Behaviour from quadrant IV to quadrant I from quadrant I to quadrant IV

 

Self-Check 1

 

textbook

  1. Complete “Your Turn” on page 415 of your textbook. Answer

  2. Complete questions 5.a., 5.b., and 5.e. on page 421 of your textbook. Answer