Algebra II / Mr. Hansen
11/18/2005

Name: _________________________

Test through §6-11

Time limit: 26 minutes (39 minutes for extended time). Calculator is allowed throughout. Point values are shown on the board.

 

Part I: Proof (25 points)

 

1.

State and prove the Change of Base formula for logarithms. Use letters a and b for the two bases involved, and use x for the unknown value whose logarithm is being computed. Be sure to include all the assumptions regarding a, b, and x.

 

 


 

Part II: Short Answer (5 points each, little or no partial credit)

All calculator results must be correct to at least 3 decimal places.

 

 

2.

Whenever we give a calculator-based answer on a quiz or test, we must provide at least ____ decimal places of accuracy. (This is supposed to be a “gift” question.)

 

 

3.

Compute log7 45: _______________

 

 

 

I am thinking of a number, x. I will not tell you what x is, but I will tell you that logx 2 » .25, logx 3 » .4, and logx 5 » .6. Estimate each of the following.

 

 

4.

logx 15 » ____________________

 

 

5.

logx 510 » ____________________

 

 

6.

logx (5/3) » ____________________

 

 

7.

Estimate the value of x itself: ___________________

 

 

8.

Give a short reason for your answer to #7: ____________________

 

 

9.

Find an approximation for y if 10y = 347. ____________________

 

 

 

 

 

 

 

 

 

 

10.

Write 300300 in scientific notation: ____________________

 

 

 

 

 

 

 

 

 

 

11.

Estimate  and give your answer in scientific notation: ___________________

 

 

 

 

 

 

 

 

 

 

 

 

12.

Write an exponential function where y is equal to something: _____________________

 

 

13.

Rewrite your equation in #12 in logarithmic form: ____________________________

 

 

14.

What name in mathematics do we give to an “adjustable constant”? Hint: The word starts with the letter P. _____________________________

 

 

15.

Simplify the expression that is written on the board.