L2 MAC Lesson on LOGARITHMS Mr. R. Singh Learning Intentions: At the end of the lesson, students should be able to: - express logs in exponential (or base index) form and vice versa - apply laws of logarithms to simplify expressions - solve problems using logs Activity: Express the following in log form Activity continued: Express the following in log form 5) You invest $4 000 in an account to save for your future studies. a) Option 1 pays 5% annual interest compounded semi-annually. What would be the balance in the account after 2 years? b) Option 2 pays 4.5% annual interest compounded annually. What would be the balance in the account after 2 years? c) At what time (in years) would Option 1 give you $100 more than Option 2? 6) Timothy was given $1 000 by his grandmother when he was 5 years old. This was invested at an interest rate of 2.5% per year, the interest being added to his investment at the end of every year. The value of his investment after 𝑛 years can be modelled by 𝐴=1 000 (1.025)𝑛 where A is the value of the investment. a) How much will the investment be worth by the time he is 10 years old? b) How much more will the investment be worth by the time he is 20 years old, compared with when he was 10 years old? c) Assuming this rate of growth continues, after how many years will the investment have doubled to $2 000 ?
