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Edexcel A2 C4 Mathematics June 2015 - Official Thread

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when do you know to take a constant outside of a function before you integrate??

I always take the constant out before integrating, i just find it easier and sometimes i helps with the later parts of the question. I don't think it makes much difference though so do what works for you

Reply 1861

ember8

Original post by Maham88

haha thanks :h:

im on question 6c, same paper, ive got all the working out but my limits are wrong even though i got them righ in part a
it says that its pi and 0, i have pi/2 +1 and 0....

Original post by jmuz

sorry one more thing,

is that a rule that could be applied to any equation in that form e.g

integrating

3^2u (wrt u) would therefore equal… 3^2u / 2ln3

Yes there is a general rule at play here; some posters have mentioned it already as perhaps a result people are meant to know. When I took C4 (I took OCR, rather than Edexcel), we weren't expected to know the result per se, but perhaps the substitution. Regardless, that is what I have tried to show.

Reply 1863

ember8

anyone know why theyve changed the limits from pi/2 +1, 0 to pi,0 in this question? attachment included

Original post by Sumz.96

How do you choose a suitable value of x for binomial expansion? I don't understand how you know what x value to substitute in the expansion..?

basically mod the x value after you've put it in the form you'll use to expand it, heres the video explaining
http://www.examsolutions.net/maths-revision/core-maths/sequences-series/binomial/formula/validity/tutorial-1.php

Reply 1865

MrBowcat

Original post by ember8

anyone know why theyve changed the limits from pi/2 +1, 0 to pi,0 in this question? attachment included

pi/2 +1, 0 are coordinates of the tangent not the limits. The limits are given in the question at the start..... It's late get some sleep man maths will do this to you.

Reply 1866

Paraphilos

Original post by ember8

anyone know why theyve changed the limits from pi/2 +1, 0 to pi,0 in this question? attachment included

You have found the coordinates of the point at which the tangent is parallel to the

x

axis; the range in question though, is the one you want to use to evaluate the integral.

Reply 1867

ember8

Original post by MrBowcat

pi/2 +1, 0 are coordinates of the tangent not the limits. The limits are given in the question at the start..... It's late get some sleep man maths will do this to you.

hahahah thanks dude, completely forgot about that

Reply 1868

ember8

Original post by Paraphilos

You have found the coordinates of the point at which the tangent is parallel to the

x

axis; the range in question though, is the one you want to use to evaluate the integral.

haha just realised, stupid mistake!

Reply 1869

Leking9

Original post by Bustamove

no, you wouldn't have... We shouldn't be discussing this here LOL, theres a econ thread.. but I'll try and keep it short...

The question didn't specifiy traditional bike manufacturers.. only stated bike manufacturers which was open to interpretation.. whether you wrote about ebike manufacturers or traditional manufacturers was fine... there was a massive uproar on this on edexcel econ 3 thread. Besides, in the extracts, some traditional manufacturers were also ebike manufacturers anyway, which will just lead to a massive mess even if it were specified...

Well, I hope you're right mate. I think I'd have gotten an a* if i were to be fully credited for my answer. Crazy considering that I had to re-learn everything within a few days

Reply 1870

Abdul Kalim

All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.

Reply 1871

Rubgangsci

Original post by Abdul Kalim

All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.

Do you want a cookie bro?

Reply 1872

Datta10

How to integrate sin3xcos5x ???

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Reply 1873

Paraphilos

Original post by Abdul Kalim

All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.

Reply 1874

TeeEm

Original post by Abdul Kalim

All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.