Free Precalculus Help
Precalculus is graded as its own course but functions as the entry fee for calculus. The topics students skim here are exactly the ones that make calculus feel impossible later.
Why precalculus grades actually slip
Precalculus is unusually wide and shallow — functions, trigonometry, logarithms, sequences, sometimes matrices — which makes it easy to pass while retaining almost nothing. The grade damage shows up in the course itself when the exam covers six chapters at once and no single chapter was ever learned to fluency.
Three topics do disproportionate harm downstream: the unit circle, because calculus assumes instant recall rather than derivation; log and exponential rules, because they reappear in every integration technique; and function transformations, because the ability to see f(x−2)+3 and know the shape without plotting is what makes later graphing fast. If you are triaging, over-invest in these three.
Free resources worth your time
Everything below is free to use without payment. The note on each one says when to reach for it, because the usual problem is not a shortage of material — it is picking the wrong kind of material for the stage you are at.
- Khan Academy — Precalculus Free course Well-sequenced and free. The trigonometry unit is the part worth your time even if the rest feels familiar.
- OpenStax — Precalculus Free textbook Free, complete, and mapped closely to how most US precalculus courses are structured.
- Professor Leonard Video channel His precalculus series is paced like a real course. Use it to rebuild a topic properly rather than patch it.
- Khan Academy — Trigonometry practice Practice Trigonometry is where precalculus grades are usually lost. Practise it separately from everything else.
What to do with the time you actually have
If you have the rest of the term
Build unit-circle recall to the point of boredom — it is the single highest-return memorisation in the whole maths sequence and it costs about twenty minutes a week. Everything else in precalculus is understanding; this part is genuinely just recall.
If you have a week
Work backwards from the exam's topic list and rank topics by how many questions they carry, not by how shaky you feel. Students routinely spend the last week on their weakest topic when it is worth four points.
If you have tonight
Drill the unit circle, log rules and the standard transformations. These are recall items, which means they are the only things that genuinely can be learned the night before.
Work out what you actually need first
Before you spend a weekend on this, get the number. If the final is worth 20% and you are sitting at 88%, an A needs 98% and a B needs 48% — those two facts call for completely different weeks. Run your real numbers through the final grade calculator, then come back and pick the plan that matches the gap. The finals-week triage guide covers how to split time across several courses at once.