Algebra 2B — Exponentials, Logs & Sequences
Part 2 of 2. Exponential growth & decay, the logarithm as its inverse (and the log laws), and arithmetic & geometric series.
Part 2 of 2. The mathematics of percentage growth — money, populations, decay — and the logarithm that runs it in reverse, plus the sums hiding inside repeated patterns.
- 01 Exponential growth & decay ELI5: exponential growth means multiplying by the same factor every step (not adding). At 7 % a year, money is ×1.07 each year — so it accelerates: the more…
- 02 Logarithms — the inverse question ELI5: a logarithm asks "what power?" — log_b(y) is the exponent you must raise b to in order to get y. It is the exact undo of exponentiation. And it…
- 03 Sequences & series ELI5: adding 1 + 2 + ⋯ + n one at a time is a slog; pairing first with last is the insight — each pair sums to n + 1, and there are n/2 pairs, giving n(n +…
next course: Trigonometry A — Triangles & the Unit Circle →