EXP015 · Powers, exponents & logarithms · Classes 11–12
Logarithms
A logarithm answers “what power?”: log_b x = y means bʸ = x.
Logarithms📐 Formula
log_b(xy) = log_b x + log_b y; log_b(bⁿ) = n
✏️ Worked example
log₁₀ 100 = 2 because 10² = 100.
🌍 Where it is used
Decibels, pH, earthquake scale and compound interest.
❓ Quick check
log₂ 8 =