Precalculus 3: Trigonometry

Our verdict: worth it — as long as the Teaching & Academics skills on the syllabus match what you actually want to learn. The regular price for Precalculus 3: Trigonometry on Udemy is $149.99. With the coupon code on this page, that falls to $9.99 — a saving of $140.00, or 93% off the standard rate Spread across 52h of on-demand video, that works out to roughly $0.19 per hour of content — cheaper than a single chapter of most printed Teaching & Academics textbooks.

A cheap price means nothing if the material is thin — here the syllabus is organized around usable outcomes. Hania Uscka-Wehlou walks you through how to solve problems in trigonometry (illustrated with 215 solved problems), in both geometrical and functional contexts, and why these methods work, you get a crash course in Euclidean geometry: angles, triangles, polygons, similar triangles (proportions), inscribed and circumscribed circles, bisectors, etc, and number pi: its definition as the ratio of the perimeter to the diameter of a disk, relation to the area of a disk, some geometrical approximations — skills meant to be used, not just watched. It has already been taken by 4,031 students and holds a 4.7-star average from verified reviews, which suggests the content holds up once learners actually apply it.

Check the prerequisites before you commit: High-school mathematics, mainly arithmetic; solving simple equations (linear and quadratic) with one unknown; some (but very few) polynomial equations will be solved during the course, but you can skip them if you want to (no problem at all; it will not affect your understanding of trigonometry); Precalculus 1: Basic notions (mainly the concept of function and related concepts; sets; logic). Best suited to learners who already have footing in Teaching & Academics. Plan for roughly 52h of on-demand video at your own pace. Lessons are delivered in English.