University:
Missouri State University
Course:
MTH 136 | Precalculus 1
Academic year:

2021
Views:

195

Pages:

9
Author:

Bennett Wheeler

Warm-Up You are offered two deals to save money: 1. You can deposit $10,000 into an account that is compounded monthly with an interest rate of 5% 2. You can deposit $12,000 into an account that is compounded continuosly with an interest rate of 4%. You will not be able to touch the money for 20 years. Which should you go with? 7.4 SOLVING WITH LOGS If there is a variable in an exponent Convert the equation to logarithm to solve  500 3  90 log 6 500  x  2 log 3 90  4x x  log 6 500  2 log 3 90 x 4 x  1.024 6 x 2 log 500 x 2 log 6 x  1.468 4x p. 505 #25-40 First column If there is more than one variable Take the log of both sides x x1 3 5 x  log 3  log 5    log 5 x x1 log 3  log 5  log 5 x x log 3   x  1 log 5 log 3  log 5 x log 3  x log 5  log 5 x log 3  x log 5   log 5 x  3.151 2 7 3x x 2 x  3log 2  log 7   2log 7 log 2  log 7 x 2 log 2  log 7 x 2 3x 3x 3 x log 2  x log 7  2log 7 3 x log 2  x log 7  2log 7 2log 7 x 3log 2  log 7 x  29.145 OR Take the log with one of the bases of both sides x x1 3 5 x 1  log 5   log 5   3 3 x x1 log 3 3  log 3 5  log 3 5 x  x   x  1 log 3 5 1  log 3 5 x  x log 3 5  log 3 5 x  3.151 x  x log 3 5   log 3 5 If there is a variable in a logarithm Convert the equation to an exponential log 4  x  4   3 log80 x  log 4  1 80 x 3 log 1 4  x4 4 x  64  4 log 20 x  1 1 x  60 10  20x 1 x 2 p. 506 #43-51 odd