AQA MFP3 - 16th June 2011

I thought it went really well! A lot easier than FP2. The last one you did the area bound by the sin curve - the area bound by the tan curve, and i got a=1/2 and b=-3/4
Got y = (Ax^4)/4 + Ax + x^2 + B for the differential equation
-2 for the limit
(2e^3)/9 for another limit

That was solid - what did everyone get for the last differential one? The one where you had to substitute...

I took the u over to the one side and the (x^3 + 1...) over to the other.

So then I had: lnu =3x^2(ln(x^3+1) )/3x^2 + c
u = A(x^3 + 1)
y = Int( Ax^3 + A1 -2x)
y = (A/4)X^4 +Ax -x^2 + B

I think I had it completely wrong... did anybody else do that?

I thought it went really well! A lot easier than FP2. The last one you did the area bound by the sin curve - the area bound by the tan curve, and i got a=1/2 and b=-3/4
Got y = (Ax^4)/4 + Ax + x^2 + B for the differential equation
-2 for the limit
(2e^3)/9 for another limit

Yeh me too was very happy when my calculator told me it was the same as what I worked out . Almost forgot how to integrate tan^2 x tho good thing I had 45 mins for the last question .

I got both of those as well. What took me a while was finding

$\frac{d}{dx}\left(\frac{2}{\cos^2 x+\sin 2x}\right)$

I was integrating one of the trig. functions instead of differentiating so I was struggling on that for a while, but I got that near the end.

I think I got (A/4)X^4 + Ax + x^2 + B. I'm fairly sure x^2 was a positive sign because u=(dy/dx)-2x

YAAAY - Actually, I think I got positive too - I just cudnt remember How was that 8 marks though?

Not sure. I did a C4-style differential equation solving stage, which involved an integration by substitution, and then a C2 integration. It felt like 8 marks to me though, because it was quite long.

I got both of those as well. What took me a while was finding

$\frac{d}{dx}\left(\frac{2}{\cos^2 x+\sin 2x}\right)$

I was integrating one of the trig. functions instead of differentiating so I was struggling on that for a while, but I got that near the end.

I didn't use substitution because it the integrand was in the form $\frac{f'(x)}{f(x)}$

But we got the same answer?

I thought the exam was ok, there were a couple of hard bits but not as many as in fp2!
What were you supposed to do for Q4 where it had the integral of sinxsin2x?

I thought the exam was ok, there were a couple of hard bits but not as many as in fp2!
What were you supposed to do for Q4 where it had the integral of sinxsin2x?

Which question is that for? Defo don't recgonise that D: