## anonymous one year ago integration help

1. anonymous

|dw:1442933005067:dw|

2. anonymous

so far this is what i have done|dw:1442933049561:dw|

3. FireKat97

thats not quite right, but you're on the right track with the substiution

4. anonymous

now im thinking of doing this let me know if im right|dw:1442933185892:dw|

5. anonymous

@FireKat97 how would you solve it

6. Empty

|dw:1442933436297:dw|

7. FireKat97

wow Im lagging like crazy right now

8. IrishBoy123

looks ok 4x - 48 + 48

9. anonymous

me 2 laggin so bad. @Empty i did a long division

10. IrishBoy123

$\dfrac{4x}{x-12}=\dfrac{4x-48+48}{x-12} = 4 + \dfrac{48}{x-12}$

11. anonymous

@IrishBoy123 does my u and du ok and taking the constant 48 outside the integral a right move?

12. anonymous

@ganeshie8 can u help out plz

13. anonymous

14. FireKat97

oh one sec

15. FireKat97

omg I made the stupidest mistake ever lol its 1 am

16. anonymous

:D

17. FireKat97

Ill write it up again hehe

18. anonymous

alright step by step plz so i can understand how you solve it :D

19. FireKat97

sure :)

20. FireKat97

hang on, I keep getting 4x + 48ln(x -12) - 48 + C

21. FireKat97

but the -48 is a constant and so is C, so could they possibly have just replaced the (C -48) with a C?

22. FireKat97

because it is a constant.... omggg

23. anonymous

|dw:1442935114878:dw|

24. FireKat97

Yup thats what I got too

25. FireKat97

this is how I did it incase you wanted to see

26. FireKat97

wait no, the 48 isn't meant to multiply by the 4...

27. anonymous

|dw:1442935301328:dw|

28. anonymous

i think u break it into 2 different integral since we are adding

29. FireKat97

yeah that looks right

30. IrishBoy123

$\int \dfrac{4x}{x-12}=\int \dfrac{4x-48+48}{x-12} \\ = \int 4 + \dfrac{48}{x-12} = \int 4 + \int \dfrac{48}{x-12} \\ = 4x + 48 ln(x-12) + C$ $\checkmark$

31. anonymous

Thanks @IrishBoy123 and @firelord for the help.. really appreciated it

32. FireKat97

:)

33. IrishBoy123

yes but C - 48 = C', ie new constant and you get same answer

34. anonymous

i got 2 more problems if you dont mind ill open a new thread and help me out :D