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# S2 Edexcel Jun 2003 help watch

1. I'm stumped on Q7d

f(x) = 3x^2 + 6x + 3 -1<=x<=0
0 Otherwise

Find P (-0.3 < X < 0.3)

I tried integrating between -0.3 and 0.3 but I get the wrong answer and i'm not sure why.

Any help appreciated. Thanks!
2. it is F(0.3) - F(-0.3)
3. yeh the mark scheme says that but to be honest, im not sure what F(0.3) means or how u do it.
4. it means P(x<=0.3)

all you have to do is bung in values in the formula for F(x) but note that
F(0.3)= 1
if you are integrating also use the fact that for all values greater than zero
F(x)=1
5. (Original post by iaN^|Uno|)
I'm stumped on Q7d

f(x) = 3x^2 + 6x + 3 -1<=x<=0
0 Otherwise

Find P (-0.3 < X < 0.3)

I tried integrating between -0.3 and 0.3 but I get the wrong answer and i'm not sure why.

Any help appreciated. Thanks!
Try integrating between -0.3 and 0, as x cannot be greater than 0.
6. thanks for the help! i didnt realise that x couldn't be greater than 0
7. (Original post by iaN^|Uno|)
thanks for the help! i didnt realise that x couldn't be greater than 0
It can be, but no point in including it as the probability is 0
8. does anyone have teh markscheme for this? pleeease! x

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