AQA A2 MFP3 Further Pure 3 – 18th May 2016 [Exam Discussion Thread]

Here you go.

how do you tell the difference between

y= Acosnx + Bsinnx for the complementary function from dy^2/dx^2 +n^2y

and y= Ae^-nx +Be^nx.

If you have
dy^2/dx^2 +n^2y , this will give k^2= +/- ni , so because it isn't real is it y=Acosx + Bsinx

dy^2/dx^2 -n^2y this will give k^2= n^2, so because it is real, is it y= Ae^(nx) +Be^(-nx)


Is this correct

Has anyone got any tips for avoiding silly mistakes? It seems as though that's where I'm loosing most of my marks

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If a 2nd order DE is set equal to a polynomial such as 3x + 4, is the trial function supposed to be ax + b or ax^2 + bx + c?

If a 2nd order DE is set equal to a polynomial such as 3x + 4, is the trial function supposed to be ax + b or ax^2 + bx + c?

Hey guys, any predictions regarding the paper? I've found 2014 No8 quite weird any other tricky questions to look at?

If a 2nd order DE is set equal to a polynomial such as 3x + 4, is the trial function supposed to be ax + b or ax^2 + bx + c?

Im stuck on that question, any help?

I just done that question but it's a bit messy lol if u can even read that

how did u get the sin(pi --(pi/6 +a)) part I don't understand

how did u get the sin(pi --(pi/6 +a)) part I don't understand

It's a triangle so all the angles add up to 180 degrees so pi radians and u already know 2 angles which are pi/6 and Alpa so you take them away from pi to get your missing angle then do sine rule

Depends. If there is no term in y, say you have
$\displaystyle \frac{\text{d}^2y}{\text{d}x^2} + 3\frac{\text{d}y}{\text{d}x} = 12x+16$,
a trial function of $px+q$ would not work in this case.