Logs – Part 2

Review of Logarithms 3 logarithm laws 3 logarithm shortcuts

Solving log equations Solving logarithmic equations takes some instinct, which only comes from practice, but to help you get you started, here is a flowchart with some possibly useful steps.

Solving Exponential/Logarithmic Equations Example Ex: Solve for x.

Solve these equations for x Solving Exponential/Logarithmic Equations Practice

Lots o’ Logs

Applications - Logarithms Ex 1. A Sidney Crosby rookie card was purchased in 2005 for $ Its value is set to double every 2 years. When will the card be worth $90.00? In 5.17 years, the card is worth $90.

Ex 2. A certain radioactive element has a half-life of 8.2 minutes. When will there be 1/10 th the original amount? It will take minutes for only 1/10 th the original amount to remain. In this case y = (1/10)A o Applications - Logarithms

Ex 3. Sarah bought a computer for $2000. Its value depreciates by 18% every two years. r = 1 – 0.18 = 0.82 This means it will be worth 82% of its value after 2 years. In one year, it went from being worth $2000 to being worth $ Dividing tells us that it is % of $2000, or a depreciation of 9.446% in one year. a. By what percentage does it depreciate every year? Applications - Logarithms

b. When is its value $99? In years her computer will be worth $99. Applications - Logarithms Ex 3. Sarah bought a computer for $2000. Its value depreciates by 18% every two years.