Pure Maths 3 Integration Part 2: Trigonometry Full Summary & Forms of Reverse Chain Rule in Depth

Описание: This video continues the Integration chapter for Edexcel IAL Pure Mathematics 3 (P3) — and we start with a full summary of ALL the trigonometry knowledge you will ever need for P3 and P4.
If your trig foundations feel shaky, this intro will sort them out immediately.

What’s covered:
—Essential trig identities and results for P3 + P4 (quick but complete recap)
—The two major forms of the reverse chain rule, explained clearly:
kf′(x) / f(x)
kf′(x) · (f(x))ⁿ
—How to recognize which form applies
—How to integrate each form confidently
—Common exam traps and pattern-spotting techniques
—Two real June 2025 P3 paper integration questions

This is the video that builds the core intuition behind reverse chain rule integrals—absolutely crucial for scoring high in P3 (because all integrals in P3 will always math one of the three reverse chain rule forms i.e. f(ax+b); kf'(x) / f(x); kf′(x) · (f(x))ⁿ) and for surviving even the harder P4 integrals which often have some terms that must be integrated using reverse chain rule methods.

AND REMEMBER: FOR P3 INTEGRATION, YOU MIGHT FIND U-SUB TAUGHT BY TEACHERS EASIER, WHICH IS FINE: YOU CAN USE U-SUBSTITUTION FOR P3, BUT IT'S NOT REQUIRED BY THE SPECIFICATION. JUST IDENTIFYING AND APPRECIATING THE THREE REVERSE CHAIN RULE METHODS IS MUCH EASIER. IT GIVES YOU THE GENERAL ANSWER FORM IN ONE STEP AND YOU DO THE CONSTANT ADJUSTMENT IN THE NEXT STEP. THAT'S WHY THESE SEEMINGLY HARD QUESTIONS ARE JUST FOR 2 MARKS. U-SUBSTITUTION MAKES YOUR WORK MUCH LONGER.
SO REMEMBER, FOR P3 Reverse chain rule standard form methods mog U-substitution.