Name _______________________________
Lab #3 – Chapter 4 – Solving Exponential and Logarithmic Equations
Read each problem carefully and show your work! Write neatly and in pencil.
Part I: Solving Exponential Functions – Give exact answers
1)
7 2x  3  7 x  5
5 x  13

2) 3
3)
10 x4  6
4)
1
9
8  2e x  52
Part II: Solving Logarithmic Functions – Give exact answers
5) log (x) + 5 = 3
6)
log 2 ( x  1)  4  0
7) log 4 ( x)  log 4 ( x  6)  2
8) ln (x + 4) + 5 = 8
Part III: Applications
9) Ryan starts a savings account with an initial investment of $5000 at 8% compounded
continuously.
a) How much money will Ryan have after 3 years? (round to the nearest cent)
b) How long will it take for his investment to double? (round answer to 1 decimal)
.03h
10) The function D(h)  10e
can be used to find the number of milligrams D of a
certain drug that is in a patient’s bloodstream h hours after the drug has been
administered.
a) How many milligrams will be present after 2 hours? (round answer to 1 decimal)
b) When the number of milligrams reaches 1, the drug needs to be administered again.
When (after how many hours) will the drug need to be administered?
(round answer to 2 decimals)
11) The population of Collin County, which follows the exponential growth model,
increased from 264,000 in 1990 to 490,000 in 2000.
a) Find the exponential growth rate, k.
(do not round k---use ALL decimals on the calculator)
b) Write the exponential growth function.
______________________t
A(t) = _________________ e
(continued on the next page)
c) What will the population be in 2012?
(round your answer to the nearest whole number)
d) When (in which year) will the population be 640,000?