Edexcel A level Maths : 7.3 The Double Angle Formulae

Pearson A level Maths, Pure Year 2 Textbook (7.3)

In this video I introduce the double angle formulae for sin, cos and tan; explaining thoroughly how it works. The next phase of the video is looking at its application.

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[Ayasir-loir]

crispy juicy tasty succulent mouth-watering question

[beamiliner]

Really useful! Got my A-levels in may, and with the new edexcel spec, the teachers really didn’t know what they’re teaching. Thanks so much for explaining so clearly!

[Drifterz]

Your videos are something else dude. Thanks so much

[kingvadanite]

For question 3, you can deduce that to get to the answer, you must remove 3cos2x whilst simultaneously getting rid of 3 cos^2x. I found it was much easier to simply write the LHS (left hand side) as cos2x + 3cos2x so that I could then write cos2x + 3(2cos^x-1). Expanding and cancelling out leaves you with the answer very quickly after doing that. All in all, really appreciating the content you've put up and would like to thank you - your videos will help me with the Autumn Exams coming up :)

[soazakaria]

Jzkallah Khairan Mr Zeeshan That really helped

[angelkapur]

hi there! i am stuck on how u got the answer to cos^theta 3:29 and how would i do cos^2 theta/2 and sin^2 theta/2?

[angelkapur]

i do not understand how the CAST diagram works instead i use the graphs, could u explain why at 9:37, why the answer is -3 instead of 1/3?

[angelkapur]

how did u obtain cos2x+1 / 2 at 11:48? why is there a plus in the numerator?

[GP-eqgh]

Hello, I’m doing the whole of a level maths in one year as i failed it last year. I got C’s in pure and failed applied. Should i start year 2 content first or year 1 content? Since September, i have done half of the year 1 textbook. I still remember a lot of the content from year 2.

Also because i am doing the whole a level in one year, how should i plan my revision? When do you think i should at least finish the whole of pure and applied by?

Finally, would you suggest that i complete all the exam questions in the textbook and then doing full practice papers for pure and applied. Then reviewing all the papers that i done and focusing on sections/topics that i got wrong.

Thank you

[username-jvee]

hello sir, are you going to do exponentials and logarithms anytime soon?