Edexcel A2 C4 Mathematics June 2015 - Official Thread

I am absolutely ******. What should I focus on? I can do binomial, partial fractions, and basic integration, and a lot of vectors.

Any suggestions on mastering vectors?


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There's no leeway in the syllabus for revolutions for basic revolutions around different lines? Where's the fun in just revolving around y=0 all the time?

Hi guys! Any tips for remembering all the methods for solving integrals?

can you leave vectors as column vectors or do you need to put in i+j+k form?

The idea has come up before.
eg 2^x differentiates to 2^xln2.
that means if i am integrating (going the other way) 2^x the answer must be something to do with 2^x . It is just a matter of sorting out the constant.
So integrate 2^x ln2 becomes 2^x
therefore integrating 2^x becomes 2^x/ln2

Hey friends
I need help

I know what the values of sin cos and tan of 30,45 and 60 are because I've used them so many times I know them by heart but I'm not sure how to find values of other angles eg 120 which is sometimes needed in integration when you need to simplify your answer (my calculator does not give them in this fraction form) my teacher told me in one particular question that had sin 2π/3 that I can just use 180-60 and figure it out like that but what if it's cos or tan?

Hey friends
I need help

I know what the values of sin cos and tan of 30,45 and 60 are because I've used them so many times I know them by heart but I'm not sure how to find values of other angles eg 120 which is sometimes needed in integration when you need to simplify your answer (my calculator does not give them in this fraction form) my teacher told me in one particular question that had sin 2π/3 that I can just use 180-60 and figure it out like that but what if it's cos or tan?

Use CAST diagrams
or find a better calculator

yo i aint got no time to find a better calculator the exam's tomorrow
I know I'm supposed to use CAST diagrams but I don't get how

Well the =36 suddenly disappeared on the line when you /9. You did it all correct, except it should be 225-36, which is 189, then divided by 9 you get 21, meaning the answer is lamda = -3 or -7

Oh no I see, you did do the cancelling correctly. I got an equation same as yours excep =36.. I'm unsure how you got to that stage if I'm honest..

is it me or is it so much easier to make stupid mistakes in C4 than C3?

well generally you can use the approach that sinx = sin (180-x) and cos x = cos(-x)
also for sin 210, draw a cast diagram. you'll see that sin210 = -sin30

I'm not your friend, but I'll give some advice.

I prefer using simple formulae to the CAST diagrams;
sin(x) = sin(180-x), sin(x)=-sin(-x)
cos(x) = -cos(180-x), cos(x) = cos(-x)
will do everything the CAST diagrams do, and are much more efficient.

Agreed


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thanks non friend!