Help with Integration general solution question

mh1985

Hi

If anyone can advise on this one it would be much appreciated:

So far I have:

u \frac {du}{dv} = v +2

(I don't fully understand this next part I'm just following the pattern from my examples, if anyone could explain that would be a big help) I know you have to separate the variables but I'm not 100% on it yet.

\int u \:du = \int v+2 dv

\frac {u^2}{2} = \frac {v^2}{2} + 2v + A

Not sure what to do next? and also whether that is correct or not?

thank you!

(edited 13 years ago)

Reply 1

Mr M

Study Forum Helper

What are you trying to do? You have integrated correctly. If you want to make v the subject multiply by 2 and complete the square.

Reply 2

mh1985

Original post by Mr M

What are you trying to do? You have integrated correctly. If you want to make v the subject multiply by 2 and complete the square.

It asks to find the general solution so I think that is make v the subject?

Reply 3

mh1985

I've got a answer on the sheet that is

u^2 = v^2 + uv + B

where has the u on the right come from?

bump

Original post by mh1985

I've got a answer on the sheet that is

u^2 = v^2 + uv + B

where has the u on the right come from?

Seemingly out of nowhere, but you might have gone wrong before you got to the stage of writing

u\frac{du}{dx} = v+2

. What was the original question?

Reply 6

mh1985

Original post by nuodai

Seemingly out of nowhere, but you might have gone wrong before you got to the stage of writing

u\frac{du}{dx} = v+2

. What was the original question?

u\frac{du}{dx} = v+2

was the original question :confused:

Reply 7

nuodai

Original post by mh1985

u\frac{du}{dx} = v+2

was the original question :confused:

Ah right; in that case, the u shouldn't be there. [In fact, it should be a 4.] I think it's just a typo; they typed "u" instead of "4"... easy enough to do :p:

Reply 8

mh1985

Original post by nuodai

Ah right; in that case, the u shouldn't be there. [In fact, it should be a 4.] I think it's just a typo; they typed "u" instead of "4"... easy enough to do :p: