Doctor Strangelove
Real Battlefield Veterinarian.
+1,758|6876
Please show me how to integrate the following.

[(x+2)/(x+1)](dx)
mkxiii
online bf2s mek evasion
+509|6644|Uk
ok, integral of [(x+2)/(x+1)](dx)...

Intergration by parts is  ∫udv/dx dx= uv - ∫v du/dx dx

so uv = ∫udv/dx dx+∫v du/dx dx

du/dx = x+2
dv/dx = (x+1)^-1

uv= (x^2+2x)((x+1)^-1) + (x+2)(log(x+1))

that sounds really wrong

i am so bad at this stuff now

Last edited by mkxiii (2010-03-03 10:19:43)

Doctor Strangelove
Real Battlefield Veterinarian.
+1,758|6876

mkxiii wrote:

integrate

im a spastic

Last edited by Doctor Strangelove (2010-03-03 10:03:20)

mkxiii
online bf2s mek evasion
+509|6644|Uk

Doctor Strangelove wrote:

mkxiii wrote:

integrate

im a spastic
tried again but i think i failed
Jebus
Looking for my Scooper
+218|6173|Belgium
i saw this a month ago in school

i already forgot how to do this
mkxiii
online bf2s mek evasion
+509|6644|Uk
i havent had to intergrate anything that like this for about 2 years so i cant do it for shit now

apparently it should be x+log(x+1)

Last edited by mkxiii (2010-03-03 10:21:33)

Jebus
Looking for my Scooper
+218|6173|Belgium
ok let me try


this is undefined integral, right?

[(x+2)/(x+1)](dx)

= ∫[(x+2).(x+1)^-1].dx

then i'd do the following, but I'm pretty certain it's wrong

NVM, so wrong
Bevo
Nah
+718|6929|Austin, Texas
integrating by parts should work just fine

cba to work it out myself, check wolfram
Doctor Strangelove
Real Battlefield Veterinarian.
+1,758|6876
Yeah, I'm not supposed to need to integrate by parts for this one.
Bevo
Nah
+718|6929|Austin, Texas
Factor out (x+2), integrate the 1/(x+1), result (x+2)ln(x+1) + C?

I dunno, i fail at calc. and i'm in calc 2.

http://www.wolframalpha.com/input/?i=integrate+[%28x%2B2%29%2F%28x%2B1%29]%28dx%29+

Last edited by Bevo (2010-03-03 10:47:32)

mkxiii
online bf2s mek evasion
+509|6644|Uk

Doctor Strangelove wrote:

Yeah, I'm not supposed to need to integrate by parts for this one.
quotient rule? =>∫dv/u=v/u+∫v/(u^2)
Sgt.Davi
Touches Himself At Night.
+300|7051|England
Integrate by parts with:

u = x+2 and dv/dx = 1/x+1 I would have thought.

Also:

mkxiii wrote:

ok, integral of [(x+2)/(x+1)](dx)...

Intergration by parts is  ∫udv/dx dx= uv - ∫v du/dx dx

so uv = ∫udv/dx dx+∫v du/dx dx

du/dx = x+2
dv/dx = (x+1)^-1

uv= (x^2+2x)((x+1)^-1) + (x+2)(log(x+1))

that sounds really wrong

i am so bad at this stuff now
...+C
Flaming_Maniac
prince of insufficient light
+2,490|7115|67.222.138.85
do long division to make it two integrals

Any reason this can't go in the homework help thread?
Doctor Strangelove
Real Battlefield Veterinarian.
+1,758|6876

Flaming_Maniac wrote:

do long division to make it two integrals

Any reason this can't go in the homework help thread?
Because it was for a quiz that I needed help with.

One that ended 19 minutes ago.

And also, it was one of those things were it starts off all like

(x+1)/(x+1)(x+3)

and then you gotta make it all like

[x+1] = (A(x+3)+B(x+1))/(x+3)(x+1)

And then factor out A and B and shit and then solve for A and B and you get two different integrals that you could solve for. However I couldn't solve for the integrals I got, because this shit sucks.
Flaming_Maniac
prince of insufficient light
+2,490|7115|67.222.138.85
you needed to divide again for one of the integrals
Arc
silly one-liner
+24|6867|Ontario
I guess this is a bit late but...

x + 2 = x + 1 + 1

=> (x + 2) / (x + 1) = 1  +  1 / (x + 1)

Which you can integrate without integration by parts.

You'd get
x + ln(x + 1)

Last edited by Arc (2010-03-03 14:16:59)

Board footer

Privacy Policy - © 2025 Jeff Minard