4756 OCR MEI FP2 22nd June 2015

Could anyone explain how to justify the signs when showing this. The mark scheme is very vague.

guys how do you go about drawing polar graphs for simple ones like r=a cos 3theta or r=a sin 4theta quickly?

it takes me ages to figure out where the dotted lines go and how to do it but sometimes you need to draw the graph for the next part of the question so i can't leave it till the end

Now that the horror of physics and annoyance of economics is done I am now free for maths

How you all?
And for those that did OCR A Physics, how was Friday for you?

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You should try to remember the "standard" curves, if you do and one comes up you will save so much time.

Just choose common values of theta to plug into your calculator, eg pi/4, pi/2, 3pi/4 etc, and try to visualise what the curve will look like.

Now that the horror of physics and annoyance of economics is done I am now free for maths

How you all?
And for those that did OCR A Physics, how was Friday for you?

Posted from TSR Mobile

i just hope a 2 mark curve comes up where you can easily visualise it by using 2 or 3 points. i am fine on most curves except the standard ones that never come up much cos they are supposed to be easier.

June 2010 the paper I am doing at the moment... 12 mark question on polar curves.

My worst nightmare (the question was actually pretty straightforward in the end).

Can someone slowly go through the substitution method of integration, mainly how you know what to substitute x as, iv attached an example of a worked solution to question 1bii) on Summer 2011.

I normally do it another method but when substitutions are required i get very confused!

Which bit don't you understand?

You notice that the denominator in the integral is of the form:

$1 + kx^2$ where k is a square number, so we can re-write this as:

$1+ (2x)^2$.

We already can tell that the substitution required is trigonometric just by looking at it, so we consider trig identities of the form "$1 + x^2$". $1 + tan^2x$ fits this nicely, so we want:

$2x= \tan u \Rightarrow x = \frac{1}{2} \tan u$

Thanks you cleared that up a bit!

Also one more question, is this a perfectly acceptable way of showing all the roots on an aground diagram... as in the lines drawn out to out point?

I take a good 2 hours to do a paper, has anyone got any advice on how to get it down to 90 minutes!!

In the past papers I've got grades ranging from As to Us... So this year's paper should be interesting 😂

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You might look at why? Are there some topics you don't get? Are you just getting better as you practise?