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# integration watch

1. Hi

does anyone know how i can integrate this

2/8-4x+x^2
2. it would just be -4+2x wouldnt it?
3. Hi!

Start off with the first argument: If f(x)=2/8x^0 with x^0 = 1, then the integration is as follows: F(x)=(0.25/1)x^(0+1).
Now, you take f(x)=-4x^1 and attempt to intergrate it in congruence with the example above.
Finally, it's the same with f(x)=x^2, f(x)=1x^2 respectively.
4. its just simpy 2x/8 -2x^2 + x^3/3 +c
hannahH93 has differentiated not intergrated...
dont forget the +c
5. thanks but how did you arrive at that answer
6. (Original post by chris007as)
Hi

does anyone know how i can integrate this

2/8-4x+x^2

Which of these did you mean?
7. the second part
8. (Original post by chris007as)
the second part
In that case, all the answers given so far are wrong - they were all for the 1st equation.
9. (Original post by chris007as)
the second part
You'll have to factorise, then split it up into partial fractions, I think.
10. (Original post by + polarity -)
You'll have to factorise, then split it up into partial fractions, I think.
Unfortuently this equation can't be factorised.
11. (Original post by starofale)
Unfortuently this equation can't be factorised.
Yeah

Complete the square?
12. (Original post by + polarity -)
Yeah

Complete the square?
Yes, that's what I was trying, but then it got into trigonometric substitution stuff
13. (Original post by starofale)
Yes, that's what I was trying, but then it got into trigonometric substitution stuff
Wow! What kind of question is this?!
14. Complete the square, do a simple linear sub to get something of the form 1/(a^2+t^2); this is a standard integral that should be in your formula booklet.
15. (Original post by DFranklin)
Complete the square, do a simple linear sub to get something of the form 1/(a^2+t^2); this is a standard integral that should be in your formula booklet.
Its in the forumla book?!?

I'd just integrated it myself when I read this
16. is it just (ln(8-4x-x^2))/x-2 + c?
17. (Original post by 1052319933)
is it just (ln(8-4x-x^2))/x-2 + c?
No, its to do with a trigonometric function. ln doesn't appear in the answer.

DFranklin's post says what to do.

18. Which, if you look in your formula booklet, integrates to:

19. (Original post by maxfire)
Which, if you look in your formula booklet, integrates to:

umm...

20. (Original post by maxfire)

I believe your mistake is here.

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