Logarithms
The question
log₉ 1/81
What is log₉ 1/81?
log₉
9² = 81
9⁻² =
log₉ = −2
- log₉ asks a question: which power of 9 lands on ?
- is 1 over 81, and a negative exponent is what writes a reciprocal: 9⁻² means 1 ÷ 9². So the power that lands on is the same one, turned over.
- So log₉ is −2. A number between 0 and 1 has a negative logarithm.
How it works.
- 01
log₉ 1/81 asks a question: which power of 9 lands on 1/81?
- 02
1/81 is 1 over 81, and a negative exponent is what writes a reciprocal: 9⁻² means 1 ÷ 9². So the power that lands on 1/81 is the same one, turned over.
- 03
So log₉ 1/81 is −2. A number between 0 and 1 has a negative logarithm.