log_b a equals log a divided by log b. Use any base you can type. log₂ 8 = log 8 / log 2 = 3. Logs as a set are in logarithms.
When the keypad has only log and ln
Product, quotient, and power rules are the other identities, in log rules. Graphing logs is in logs in Desmos.
The short list is in ACT Math formulas.
The bottom line
log_b a = log a / log b. Same for ln in the numerator and denominator.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
This article offers general ACT prep guidance. The ACT can change from year to year, including its format, scoring, policies, test dates, and fees, so always confirm the latest details on the official ACT website at act.org before you make decisions. ACT® is a registered trademark of ACT, Inc. thirty-six is not affiliated with, endorsed by, or sponsored by ACT.