Diff eq's help

[Gibson486]

I am trying to solve this differential equation. dy/dx=(x+y+3)^2.

It is not seperable, so you have to substitute.

Hence, v=x+y+3, in turn, y=-3-x+v.

This is where i am lost. I am looking at my notes and it says that this should lead to an equation dy/dx=1+v^2. HOw do i get to that equation?

edit: titile changed due to popular (2 people mentioned it) demand

 

[Spoooon]

I always called it Diff EQ.

 

[phatj]

Well if you can derive implicitly...

(x+y+3)^2

2*(x+y+3) + 1 + (dy/dx) + 0

dy/dx = -1 - 2*(x+y+3)

 

[MrDudeMan]

Originally posted by: Gibson486
I am trying to solve this differential equation. dy/dx=(x+y+3)^2.

It is not seperable, so you have to substitute.

Hence, v=x+y+3, in turn, y=-3-x+v.

This is where i am lost. I am looking at my notes and it says that this should lead to an equation dy/dx=1+v^2. HOw do i get to that equation?

what math are you in? this is relatively simple

 

[Gibson486]

what math are you in? this is relatively simple

read my title

 

[HonkeyDonk]

Originally posted by: Spoooon
I always called it Diff EQ.

Yup, it is Diff EQ. I've seen it as diffy-q, diffe-q, diffie-Q, any version of diffy, then Q. I always want to punch whoever types that cuz it's FREAKIN' DIFF EQ (diff is short for differential, EQ is short for equation)

haha...