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AQA A2 Mathematics Pure Core 4 MPC4 - 17th June 2016

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https://www.youtube.com/watch?v=FMLekIfepig&index=1&list=PL3DEBFD1C07EFB431
I think they might end up doing something like this for the differential equation question, sneaking in a double angle formula.
Reply 101
Original post by Mowerharvey
How do you turn an obtuse angle into an acute angle, and would we be asked to do this?

Someone please correct me if I'm wrong! Look at the Jan 12 paper and it said that sinB=0.5 is obtuse. Is you do sin^-1(0.5) you get 30 degrees. To get your obtuse angle, draw your CAST diagram(some people may use the graph method) do 180-30 to get your obtuse angle. You know if you're right because if sine is positive it means tan will be negative.
how do u intergrate sin^4x
Can someone please tell me how to do question 6c on june 2015 paper?! Thank you!
Original post by harjit28
how do u intergrate sin^4x


Write sin^4 x as (sin^2 x)^2. Then replace the sin^2 x using the rearranged cos2x double angle identity. Expand, then repeat the process until you remove all the powers, then complete the integration.
Original post by Dapperblook22
Write sin^4 x as (sin^2 x)^2. Then replace the sin^2 x using the rearranged cos2x double angle identity. Expand, then repeat the process until you remove all the powers, then complete the integration.

erm.... what?
Original post by harrybo6
erm.... what?


IMG_1497.jpg
Original post by Dapperblook22
IMG_1497.jpg

oh i thought he said sin(4x)?
Original post by harrybo6
oh i thought he said sin(4x)?


He said sin^4x, where the ^4 means to the power of 4
Original post by Dapperblook22
IMG_1497.jpg


ahhhh okay nvm, is see he put sin^4(x) now, my bad:') how would you integrate sin^2(2x) btw?:smile:
Original post by harrybo6
ahhhh okay nvm, is see he put sin^4(x) now, my bad:':wink: how would you integrate sin^2(2x) btw?:smile:


With sin^2(2x), use a similar process. Replace it by rearranging the cos(2x) double angle identity, except in this case x is substituded for 2x.
(edited 7 years ago)
For 2015 4a2, how do we know that x=1/3?

The binomial expansion question:

http://filestore.aqa.org.uk/subjects/AQA-MPC4-P-QP-JUN15.PDF
Original post by Arima
if anyones looking for extra vector/parameter/decay questions try looking through some of the edexcel papers

http://www.physicsandmathstutor.com/a-level-maths-papers/c4-solomon/


The AQA vector question are so confusing in comparison to the edexcel ones... Every mark scheme theres a different way to work out the same question its stupid
Original post by Dinasaurus
For 2015 4a2, how do we know that x=1/3?

The binomial expansion question:

http://filestore.aqa.org.uk/subjects/AQA-MPC4-P-QP-JUN15.PDF



Well you know (8+3x)^-2/3
so rearranging the second one which is (1/81)^1/3
you can say 1/(81)^1/3
then (81)^-1/3
then (9^2)^-1/3
so (9)^-2/3
can equal that to the first equation
9^-2/3=(8+3x)-2/3
so 9=8+3x
1=3x
1/3=x :smile:
Original post by fpmaniac
The AQA vector question are so confusing in comparison to the edexcel ones... Every mark scheme theres a different way to work out the same question its stupid


They usually allow multiple ways to work out the vector questions, any valid way will be accepted
Can someone please tell me how to do question 6c on june 2015 paper?! Thank you!
When working out the angle between two vectors, should we have the vectors facing away from the angle or towards before applying the formula?
Original post by ama1234a
When working out the angle between two vectors, should we have the vectors facing away from the angle or towards before applying the formula?


Both vectors towards the angle or both vectors away from the angle will work. However you cannot have one going towards and the other going away (unless the angle is 90 degrees, in which case it does not matter).
Can someone explain how to do 5c from 2015's paper for me as well,
Original post by Dapperblook22
Both vectors towards the angle or both vectors away from the angle will work. However you cannot have one going towards and the other going away (unless the angle is 90 degrees, in which case it does not matter).


Thank you so much for clearing that up! Can I ask why it doesn't matter if the angle is 90?

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