Mathematics · a topic
Trigonometric identities, Taught not just answered.
A real-time, 1:1 lesson on Trigonometric identities: an AI teacher explains it out loud while it visualizes every step. Interrupt it, ask why, and it checks you got it, in 26 languages.
The idea
What is Trigonometric identities?
Trigonometric identities are equations relating sine, cosine and tangent that hold for every angle. The core one, sine squared plus cosine squared equals one, is the Pythagorean theorem applied to a point on the unit circle. From it and the angle-addition formulas come the double-angle, half-angle, product-to-sum and sum-to-product identities. They let you rewrite messy expressions into simpler forms, solve trigonometric equations, and are indispensable later for integrating functions and analysing waves.
Where it appears: Class 10 and 11 CBSE, GCSE and A-level, IB Mathematics, SAT and ACT, JEE, pre-calculus.
Where learners get stuck
Why Trigonometric identities is hard
There seem to be dozens of formulas to memorise, so students rote-learn instead of deriving them from the unit circle and the two addition formulas, and then misplace a sign in the cosine addition rule.
The picture a good explanation starts with: A unit circle with a point at angle theta, its horizontal leg labelled cos theta and vertical leg sin theta, forming a right triangle with hypotenuse one.
A lesson, step by step
How a lesson on Trigonometric identities goes
01
Ask
Type or say "How can I prove an identity without just guessing manipulations?" in your own words, in any of 26 languages.
02
Plan
The tutor plans a storyboard, one picture per idea, starting with a unit circle with a point at angle theta, its horizontal leg labelled cos theta and vertical leg sin theta, forming a right triangle with hypotenuse one.
03
Explain
It explains Trigonometric identities out loud while the picture builds step by step, pitched to your level (Class 10 and 11 CBSE and up).
04
Interrupt
Say "wait, why?" or type a doubt: it stops, answers over the picture, and carries on. Ask for a different explanation any time.
05
Check
A checkpoint question makes sure the idea landed, and Test Lab keeps the practice going.
06
Your notes
Upload a PDF or a photo of your class notes or a past paper and the lesson follows your textbook's terms.
Ask it anything
Questions learners ask about Trigonometric identities
- How can I prove an identity without just guessing manipulations?
- Why does cos of a plus b have a minus sign?
- Which identities do I really need to memorise?
Any of these, or your own, typed or spoken. The tutor answers on the picture and adapts to how well you are following.
Questions
Asked, Answered
Can LetMeTeach explain Trigonometric identities?
Yes. Ask in your own words and the tutor plans a lesson on Trigonometric identities: it starts with a unit circle with a point at angle theta, its horizontal leg labelled cos theta and vertical leg sin theta, forming a right triangle with hypotenuse one. Then it explains each step out loud as the picture builds, stops when you say "wait, why?", and ends with a checkpoint question.
Where does Trigonometric identities come up?
Class 10 and 11 CBSE, GCSE and A-level, IB Mathematics, SAT and ACT, JEE, pre-calculus. The lesson is pitched to your level and the exam or curriculum you follow, and you can upload your own notes or past papers so it uses your textbook's terms.
Can I learn Trigonometric identities in my own language?
Yes. LetMeTeach teaches in 26 languages and plans the lesson in the language you choose rather than translating an English one, so the terms match what your textbook says. The Free plan includes 7 hours a month with no card.
Last updated
Learn Trigonometric identities, Starting now.
Ask "How can I prove an identity without just guessing manipulations?" and watch the answer drawn. The Free plan needs no card.