Complex Numbers (Year 2) 6 • Expressing powers of sin/cos in terms of sin/cos(nx) • CP2 Ex1D • 🎯

Edexcel Core Pure Year 2

Weds 7/10/20

[mrfreerunners]

Your huffing just summarises what its like to do Further Maths year 2 haha - I love the rawness

[facts-ecyi]

Hey Mr Bicen, when you're referring to the questions that you want your students to complete, such as cp2 ex1d, is this a textbook you are referring to, if so, could you tell me which textbook it is, please?

[angelkapur]

Great video ! Appreciate it! I have a question tho.. how come at 15:06 u changed to cos theta when (y did u not put sin theta) also Idk how to integrate cos/sine.. could I explain how u did it? Thanks!

[jamiecroll]

When we say z = cos(theta) + isin(theta), what are we saying happens with the modulus (r) part of it? Is it equal to one (if so why), and if not, where has it gone?

[BBK]

you know if you added (z + 1/z) or (z - 1/z), could you do the previous type of question, the one with cos 6θ and sin 6θ (6 is just an example)? i am trying to understand why something so similar and derived by the same thing cannot work for vice-versa questions. the power of and just a different theta value?

[TheObloINATOR]

think notation is much nicer and easier if you wrote z^n + z^-n as opposed to so many fractions

[BBK]

also at 15:43, these "hence" questions, say you didn't work out the previous part, have you now just lost all the marks for part b because you dont know how to do part a?

[VK-ilkv]

how do i know if i need to use those new formulas and not expand use binomial expansion?

[gobanj]

how do I do Q4 in chapter 1D, where both trig functions are combined, this reoccurs in Q5, and I can't seem to find anything online about this, I tried to start with (2isin@)^6 then change sin^2 to 1-cos^2 but i cant reach the answer, i also tried doing (2cos@)^2 multiplied to (2isin@)^4 and resulted in a more complicated answer

[nandoboiii]

The problem for me is when they mix and sin and cos together and expect you to integrate it, like Question 5 part b and c in exercise 1D