* Graphing Calculator activities with  Logarithmic Functions *  Exercise 1 *

 

The graphs of   Logarithmic Functions  are a simplistic and unique set of curves.

There are two fundamental sets of Logarithmic and Exponential Functions to be investigated.

To understand Loagarithmic Funcsitons, it is necessary to also understand Exponential Functions.

Log B N = E                BE  = N          Anti Log B N = E

Graphing Calculators are extremenly useful with the investigation of Logarithmic & Exponential functions.

 

The activities below will start with Common Log Functions then switch to Natural Ln Functions.

 

A review of Logarithmic Functions might be helpful.    Let's try some exercises with a Graphing Calculator.

Remember all you have to do is type in the GC Mode of the equation and press enter.

Remember to use  *  for multiply    and    /  for divide    and     for exponents.

Maybe,  print out this page before starting this Graphing Calculator activities.

 

 

1. Using the review on Logarithmic Functions, predict the shape of this graph.

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y = Log X          Math Mode:    Y = –Log X

GC Mode:     Log X          GC Mode:    – Log X     

 

2. Using the review on Logarithmic Functions, predict the shape of this graph.

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y = Log (–X)         Math Mode:    Y = –Log (–X)

GC Mode:     Log (–X)          GC Mode:     –Log (–X)     

 

 3. Using the review on Logarithmic Functions, predict the shape of this graph.

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y = Log (X+2)         Math Mode:    Y = Log (X–2)

GC Mode:     Log (X+2)          GC Mode:     Log (X–2)     

 

4. Using the review on Logarithmic Functions, predict the shape of this graph.

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y =4* Log X          Math Mode:    Y = –4*Log X

GC Mode:    4* Log X          GC Mode:    –4* Log X     

 

5. Using the review on Logarithmic Functions, predict the shape of this graph.  Note Ln not Log!

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y = Ln X          Math Mode:    Y = –Ln X

GC Mode:     Ln X          GC Mode:    – Ln X     

6. Using the review on Logarithmic Functions, predict the shape of this graph.  Note Ln not Log!

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y = Ln (–X)         Math Mode:    Y = –Ln (–X)

GC Mode:     Ln (–X)          GC Mode:     –Ln (–X)     

 

 7. Using the review on Logarithmic Functions, predict the shape of this graph.  Note Ln not Log!

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y = Ln (X+3)         Math Mode:    Y = Ln (X–3)

GC Mode:     Ln (X+3)          GC Mode:     Ln (X–3)     

8. Using the review on Logarithmic Functions, predict the shape of this graph.  Note Ln not Log!

Note the difference between the left one and the right one.    Why difference?

Math Mode:    Y =5* Ln X          Math Mode:    Y = –5*Ln X

GC Mode:    5*Ln X          GC Mode:    –5*Ln X     

 

 

Click on one of the Online Calculators:  I like the first one but they are all great!

 

   GCalc!  The equation box is at the top of the screen.

Oh yel, you have to press the Click to Start GCalc button.

Click the Reset Button (Top Right) and Yes to clear screen.

 

    CoolMath Graphing Calculator   The equation box is at the top of the screen.

Click the Cls button at the bottom right of commands to clear screen.

 

  GraphIt!   The equation box is at the bottom of the screen.

Oh yel, you have to press the  Plot It!  at bottom left of screen.

Also, click the check mark in front of grid before starting to show grid.

Also, typing in a new Linear Function automatically clears the screen.

 

Tom Love                        Malone College                     Fall 2003