Complex Numbers (Year 2) 7 • Sums of Series pt.1 • CP2 Ex1E • 🎯

Edexcel Core Pure Year 2

Weds 7/10/20

[browncow]

Just want to say how grateful I am to you! I am self-studying this material, and your explanations and walk-throughs are invaluable when it comes to knotty sections like this one. This is a public service you are providing; it is very inspiring.

[abi_]

Thank you so much, I found complex numbers really difficult - especially the sums of series.

[joekinder]

Got my second pure further maths paper tomorrow and I want to say thanks for helping me with the last minute revision!

[jamiecroll]

At 8:00 with the second example, you said it is better if we put it in exponential form. I was wondering why we need to do that. How come we couldn't keep it as how it originally was.

[jamiecroll]

With the equations at the beginning why are we going from r=0 to n-1 and not r=1 to n? Since our last number is n-1, wouldn't it be n-1 lots of numbers (or because it starts at 0 does it play a factor) and i am confused why it is z^n and not z^n-1.

[BBK]

just a simple q but why do you use the alternative formula instead of (1 - r^n), you use (r^n - 1)?

[KiranPatel-wljz]

You write that n means 'number of terms' in the sum of geometric series formulae, but that formula doesn't work for a series that, say, starts at r=5 and finishes at r=10. I am confused at 5:00 why you chose n to equal 9, and more specifically what n means in this formula, because sometimes the textbook writes series starting from 1 to n, and sometimes from 0 to n-1.

[rozhakram]

could you please explain how you got 64 from 64e^2pi i?

[BBalachanthiran]

Please kindly let me Know what is name of the whiteboard you using. Thank you. Your videos are great.

[BBK]

if we look at all the terms up till n, why do we end the summation at n-1?

[kyedefriend]

@2:33 why were the equations in the orange box multiplied by -1?

[SilverWolf-hzhm]

Can you make a video on cp2 chapter 4 volumes of revolution?