- #1
Minutemade
- 1
- 0
Ok, so a teacher showed an example in class awhile back. So I am going over my notes right now, and I don't understand a certain part of the problem.
Also I am new to the forums and its my first time posting here, so please push me in the right direction if i make a mistake.
integration of (x-2)(1/2)/(x+2)
the solution is: 2(x-2).5 - 4tan-1((x-2).5/2) + C
Basically what i tried doing, is:
u2 = x-2
u = (x-2).5
2u du = dx
which after a few steps leads me to:
2u - 8(integration of (u2 +4)-1)
After this i stop understanding the problem a little...
From here i sub the root x-2 back in as u and u2 as x-2, which gives me:
2(x-2).5 - 8ln|x+2| which is wrong i think...
The way the example continues is as such:
u2 = 4z2
u = 2z
du = 2 dz
2u - ((8)(2)/4) integration of dz/ (z2 +1)
which gives the answer given above...
Basically i don't understand why we want to sub in another letter for u2, and why i can't get the same answer when i sub in the (x-2).5 earlier.
Also I am new to the forums and its my first time posting here, so please push me in the right direction if i make a mistake.
integration of (x-2)(1/2)/(x+2)
the solution is: 2(x-2).5 - 4tan-1((x-2).5/2) + C
Basically what i tried doing, is:
u2 = x-2
u = (x-2).5
2u du = dx
which after a few steps leads me to:
2u - 8(integration of (u2 +4)-1)
After this i stop understanding the problem a little...
From here i sub the root x-2 back in as u and u2 as x-2, which gives me:
2(x-2).5 - 8ln|x+2| which is wrong i think...
The way the example continues is as such:
u2 = 4z2
u = 2z
du = 2 dz
2u - ((8)(2)/4) integration of dz/ (z2 +1)
which gives the answer given above...
Basically i don't understand why we want to sub in another letter for u2, and why i can't get the same answer when i sub in the (x-2).5 earlier.