What are the laws of logarithms?
- Two of these were seen in the notes Logarithmic Functions
- Beware …
- … log (x + y) ≠ log x + log y
- Results apply to ln too
How do I use the laws of logarithms?
- Laws of logarithms can be used to …
- … simplify expressions
- … solve logarithmic equations
- … solve exponential equations
- Remember to check whether your solutions are valid
- log (x+k) is only defined if x > -k
- You will lose marks if you forget to reject invalid solutions