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Edexcel A2 C4 Mathematics June 2016 - Official Thread

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Hi guys this might be a bit of a stupid question, but when it comes to differential equations with trignometry, how do you know if it degrees or radian mode??

Reply 3741

BrainJuice

I'm technically in year 12 since I'm resisting most modules, does anybody know if I can retake C4 if I don't do well enough?

Reply 3742

math42

Original post by kosvengali

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Could someone explain to me integration by recognition?

It is literally just using your knowledge of "standard" integrals or derivatives to get an integral. For instance if you see something like (7x + 1)^2, you know that this will have integral (7x + 1)^3 multiplied by some constant, and all you need to do is find that constant. (to demonstrate, by the chain rule and standard derivatives, the derivative of (7x + 1)^3 is 3*7*(7x + 1)^2 = 21(7x + 1)^2, so to get the desired outcome you would have to multiply by 1/21)

Reply 3743

Engineerrookie

Original post by NotoriousS

Have you got any examples of what you mean?

Do you mean reverse chain rule???

Reply 3744

Brailey

Original post by BrainJuice

I'm technically in year 12 since I'm resisting most modules, does anybody know if I can retake C4 if I don't do well enough?

Yes you can

Reply 3745

Covington4

Original post by ombtom

Never switch them.

can you not switch them nd multiply everything by -1?

Reply 3746

Simple Harmonic

Original post by lordoftheties

For part b, why cant I just change my y and x into sin^2(t) and Cos^(t) and input the values of x into the Sin^2(x) Cos^2(x) identity? The mark scheme has a different method and a different answer. Im sure Ive used the method I mentioned before and got them right...

What paper is that?

Reply 3747

TSRPAV

Original post by Engineerrookie

Hi guys this might be a bit of a stupid question, but when it comes to differential equations with trignometry, how do you know if it degrees or radian mode??

When integrating and differentiating ALWAYS use radians as its the standard unit.

Reply 3748

Supermanxxxxxx

ImageUploadedByStudent Room1466711227.425648.jpg

Anyone explain how you get from the 2(4ln2)^2 value to 32(ln2)^2

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Reply 3749

kelvin1338

Guys, for this exam, do we need to memorise formulas for volumes and surface areas (i.e. for cones and other 3d shapes)? or are they always given in the question

Reply 3750

math42

Original post by M&F

No I Dont think it does I think You have to always do the OC - A where A is the given vector and C is what you are trying to find.

Its dosent work if you do A - OC

Well the vector A + 5AC = A + 5(OC - OA) is clearly equal to the vector A -5(-AC) = A -5(OA-OC)

Reply 3751

math42

Original post by kelvin1338

Guys, for this exam, do we need to memorise formulas for volumes and surface areas (i.e. for cones and other 3d shapes)? or are they always given in the question

that kind of stuff should be given

Reply 3752

Brailey

Original post by kelvin1338

Guys, for this exam, do we need to memorise formulas for volumes and surface areas (i.e. for cones and other 3d shapes)? or are they always given in the question