*Unofficial mark scheme* Edexcel C2 Maths 24th May 2017

was one of the answers -3-root3 and -3+root3

When you root (3sinx -1), you get +-root2 as part of the other side. This gives two sets of two results.

Agree with all of these except (what I assume) is your answer to 7i). The first log one

Pretty sure was 4a^3-a



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Agree with all of these except (what I assume) is your answer to 7i). The first log one

Pretty sure was 4a^3-a

I also got that m8

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Am I the only one who got -171585 for the sum?

You don't find the unshaded area you do a tingle from x=1 to x=2 and calculate area of triangle and add it to the integrated area from x=1 to x=-0.25

How the hell did you get four solutions for the trig question??? I only got two and even then my answers were 31 degrees and 328 degrees???

Because u draw a sine graph to get 109.5

How the hell did you get four solutions for the trig question??? I only got two and even then my answers were 31 degrees and 328 degrees???

i got that too

You can't use Pythagoras, it wasn't a right-angled triangle.
You need to use cosine rule to work out the length BC, and then sine rule to find that sin(x) is approx. 0.987 (forgot exact value), and then you need to realise that a positive sin value can happen twice before 180 degrees, meaning that its either x or 180 - x.
Both are valid since (180 - x) + 50 < 180, meaning that the third angle WILL be positive.

EDIT:
By working out the length of BC as 12.554 (via cos. rule), you get
16*sin(50) / 12.554 = sin(x) which is approx. 0.9763
arcsin(0.9763) is approx 77.5, with the second solution being 180 - 77.5, which is 102.5

So the actual solutions for this q. are 77.5, 102.5 (both are valid)

to factorise fully f(x) (the cubic equation) could you put a minus sign at the front with 3 sets of brackets or does it have to be (7-3x)

Heya everyone, did no one get for q2) x = 70.5 and 59.5,

Since sine rule and another angle is 180-50-70.5 = 59.5 only other possible angle. How did people get x = 109.5 out of 180 degrees??!

You found the other angle in the triangle you were meant to find the 2 possible values of x so 180-70.5