Edexcel C3,C4 June 2013 Thread

Is it just me or are c4 solomon papers quite nice? I've found them easier than the past paper I just looked at, whereas c3 solomon are so hard :/

Yeah i'm finding them strangely easy, only done 4 though so i dunno about the rest of them i'm not complaining though, hopefully this means that the real exam will be okay

I think they will definetly have long intergration questions e.g. 7/8 markers, they will try to make the differential equations harder by trying to embed an exponential quadratic or some sort.

Perfect! Thanks, I think I'm going to just memorise that anyway haha.

Also, How do I integrate $2^t$

Thanks

good you pointed that out. in the january 2013 paper you had to differentiate y=(2^t) - 1, i would of though after differentiating you get dy/dx = [(2^t) - 1]ln2 but in the mark scheme it's dy/dx = (2^t)ln2. reason why im confused because when you get to the step dy/dx = yln2 you sub in for y. but they subbed in only the first part of y; "2^t" when in fact y= (2^t) - 1

Several ways.

Firstly, you could write it as $e^{\ln 2^t}=e^{t \ln 2}$ which you can probably integrate.

Or, you could take a substitution of $u=2^t$.



You need to differentiate the $2^t$ and the 1 separately.

this is crazy ! im finishing the soloman papers within 45 minutes and getting above the 85% each time i think i should do exam papers since i believe there harder, right? what do you lot think? because i know for sure it should not take 45 mins to finish a soloman paper !

this is crazy ! im finishing the soloman papers within 45 minutes and getting above the 85% each time i think i should do exam papers since i believe there harder, right? what do you lot think? because i know for sure it should not take 45 mins to finish a soloman paper !

Heya could someone help me with this question? It's substitution.

its question 3 on the exam style paper on page 142 in the Edexcel textbook.

Heya could someone help me with this question? It's substitution.

its question 3 on the exam style paper on page 142 in the Edexcel textbook.

well firstly you would differentiate u = 5x +3 to give you du/dx = 5, rearrange it to give du/5 = dx {also note that x = (u-3)/5} then change the limits by subbing in 3 and 0 into u = 5x + 3 to give you 18 and 3 respectively. once you have done those steps you are good to go.



p.s. quite ironic that a few weeks back i was worried about integration and you told me substitution is crazy and now im helping you hahaa

Not that one! It's the question where they're asking you to substitute x = secθ

weird, i aint got that the one i showed you is my question 3 in the exam style paper hmm. what the question then?

We have different textbook papers? Oh no wonder there are no solutions available on the livetext for this paper! Uh give me a second i'll take a picture and attach it yeah?

The integration by substitution question?

What have you tried?

okay

well firstly you would differentiate u = 5x +3 to give you du/dx = 5, rearrange it to give du/5 = dx {also note that x = (u-3)/5} then change the limits by subbing in 3 and 0 into u = 5x + 3 to give you 18 and 3 respectively. once you have done those steps you are good to go.



p.s. quite ironic that a few weeks back i was worried about integration and you told me substitution is crazy and now im helping you hahaa

lol that question is on Q3 page 140 not 142