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March 29, 2024, 01:28:38 am

Author Topic: 3U Maths Question Thread  (Read 1230270 times)  Share 

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RuiAce

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Re: 3U Maths Question Thread
« Reply #525 on: August 09, 2016, 04:06:23 pm »
+2
guys for this i got 124, but the answer is 9420??!?!



RuiAce

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Re: 3U Maths Question Thread
« Reply #526 on: August 09, 2016, 04:15:44 pm »
+1
guys for this question how do you do it? i just cant figure out the last lines.



conic curve

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Re: 3U Maths Question Thread
« Reply #527 on: August 09, 2016, 09:12:30 pm »
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How would you do this question?

This is from the cambridge extension questions part of the book so it might be out of syllabus


massive

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Re: 3U Maths Question Thread
« Reply #528 on: August 09, 2016, 10:04:19 pm »
0
guys,how do you do part ii??

wait i think i got it; do you just expand and equate constants?
« Last Edit: August 09, 2016, 10:14:42 pm by massive »

RuiAce

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Re: 3U Maths Question Thread
« Reply #529 on: August 09, 2016, 10:19:54 pm »
+1
guys,how do you do part ii??

wait i think i got it; do you just expand and equate constants?
Yes. (Technically equating coefficients)

I have a feeling you may need the symmetry property nCk = nCn-k though.

massive

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Re: 3U Maths Question Thread
« Reply #530 on: August 09, 2016, 10:25:51 pm »
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I have a feeling you may need the symmetry property nCk = nCn-k though.

Whats this :O. Can you teach me what it is? (please)

massive

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Re: 3U Maths Question Thread
« Reply #531 on: August 09, 2016, 10:31:36 pm »
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Guys for part ii, i can see that u have to integrate, but why are there the negative and positive signs. If u let x= -1 you'll get that but opposite to what you have to prove :S

RuiAce

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Re: 3U Maths Question Thread
« Reply #532 on: August 09, 2016, 10:34:32 pm »
+1
Whats this :O. Can you teach me what it is? (please)



« Last Edit: August 09, 2016, 10:39:50 pm by RuiAce »

RuiAce

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Re: 3U Maths Question Thread
« Reply #533 on: August 09, 2016, 10:37:38 pm »
+1
Guys for part ii, i can see that u have to integrate, but why are there the negative and positive signs. If u let x= -1 you'll get that but opposite to what you have to prove :S


Note that I use a definite integral to save me from the need of finding a constant of integration, and then just subbing in a new value for x

massive

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Re: 3U Maths Question Thread
« Reply #534 on: August 09, 2016, 10:37:55 pm »
0



I think we just touched on it in class, but i'll keep it in mind from now on lol thanks!

massive

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Re: 3U Maths Question Thread
« Reply #535 on: August 09, 2016, 10:45:38 pm »
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Note that I use a definite integral to save me from the need of finding a constant of integration, and then just subbing in a new value for x

but how do you get the alternating positive and negative signs? for e.g. when u integrate, the second term is x^2, how can that be negative :S

RuiAce

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Re: 3U Maths Question Thread
« Reply #536 on: August 09, 2016, 10:49:10 pm »
+1
but how do you get the alternating positive and negative signs? for e.g. when u integrate, the second term is x^2, how can that be negative :S
What do you mean?

By putting -1 on the bottom you're doing F(0) MINUS F(-1), where F(-1) is the antiderivative of that expansion

massive

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Re: 3U Maths Question Thread
« Reply #537 on: August 09, 2016, 10:51:42 pm »
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What do you mean?

By putting -1 on the bottom you're doing F(0) MINUS F(-1), where F(-1) is the antiderivative of that expansion

Yeah but aren't all the signs positive after that?

RuiAce

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Re: 3U Maths Question Thread
« Reply #538 on: August 09, 2016, 10:57:22 pm »
+2

What do you mean they're "all" positive? By substituting in -1 and not +1 we force the signs to alternate.

massive

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Re: 3U Maths Question Thread
« Reply #539 on: August 10, 2016, 12:40:25 am »
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guys how do you do part ii?