Seperation of variable question.

SvenBee · 2008-04-15 07:50:35

Find the general Solution:

Now, I worked it out and here are the steps:

Now there's a missing step in there when you get rid of the natural log of y by raising e to each side (if you get what I mean) and that's what I don't understand.

Could someone please help?

Last edited by SvenBee (2008-04-15 07:56:51)

LuisRodg · 2008-04-15 08:06:38

Last edited by LuisRodg (2008-04-15 08:13:08)

SvenBee · 2008-04-15 08:14:08

I get that up until where the C comes from. How does it fit in to place?

Because isn't

technically supposed to be written as ? Since the constant is added directly after the integration step.

Last edited by SvenBee (2008-04-15 08:16:16)

LuisRodg · 2008-04-15 08:16:07

Your initial solution had to include a +C as a result to the integral (which you didnt put). You know when you do an integration you always put a +C in the end. However, in this case the +C was part of the ln(y) solution. So when you raise e to both sides, thats how you get e^C

SvenBee · 2008-04-15 08:17:22

Yeah, I edited, sorry.
But what I don't understand is how you get

mathsyperson · 2008-04-15 10:23:51

It doesn't really matter whether you have e^C or C, since they're both arbitrary constants anyway.
What I'm worried about is whether it should be added to or multiplied by the rest of the RHS.

LuisRodg · 2008-04-15 12:16:36

Rhs?

SvenBee · 2008-04-15 12:32:17

I still don't understand how you would find the C (whether it's e^C or C), and I know that it's still a constant but I want to know HOW it's done for my own knowledge. It's really stumping me.

LuisRodg · 2008-04-15 13:13:20

I dont understand your question?

You dont find the C unless your told to and in that case then they'd have to provide some function values in order to find the C.

Do you understand what the C means when doing an integral?

SvenBee · 2008-04-15 14:08:38

WOW!!! I wrote the wrong thing for the answer in my initial post.

e^c is supposed to be multiplied by the whole square root.

I'm soo sorry for the confusion. That's what I don't get, why it's multiplied and not added. And yes, lol, I know what C represents in the integral.

LuisRodg · 2008-04-15 14:12:22

Ok then can you write the correct answer so I can see what your referring to?

SvenBee · 2008-04-15 14:35:40

LuisRodg · 2008-04-15 14:46:08

I will get thinking about the e^C in a sec. But I was going over your first post and you said that:

But isnt this wrong? Isnt:

SvenBee · 2008-04-15 16:19:08

There isn't supposed to be a 9 there. I need to check my stuff b4 I post it. I'm sorry again. I'll just ask my teacher tomorrow, my mistakes are really adding up and not making this easy. Sorry.

Last edited by SvenBee (2008-04-15 16:19:32)

LuisRodg · 2008-04-15 16:22:11

Its ok.

But your right. If you have too much mistakes then it just makes it really hard to follow a discussion.

Anyways, please post what your teacher says as I'd like to know as well.

SvenBee · 2008-04-16 08:13:35

Here's all the steps and the answer:

LuisRodg · 2008-04-16 08:55:54

Very simple. Just couldnt think of it

SvenBee · 2008-04-16 14:29:55

We weren't thinking algebraically enough, lol.

Daniel123 · 2008-04-17 06:16:02

If only you posted this 2 days later.. I learnt it today

Last edited by Daniel123 (2008-04-17 06:16:22)

Math Is Fun Forum

#1 2008-04-15 07:50:35

Seperation of variable question.

#2 2008-04-15 08:06:38

Re: Seperation of variable question.

#3 2008-04-15 08:14:08

Re: Seperation of variable question.

#4 2008-04-15 08:16:07

Re: Seperation of variable question.

#5 2008-04-15 08:17:22

Re: Seperation of variable question.

#6 2008-04-15 10:23:51

Re: Seperation of variable question.

#7 2008-04-15 12:16:36

Re: Seperation of variable question.

#8 2008-04-15 12:32:17

Re: Seperation of variable question.

#9 2008-04-15 13:13:20

Re: Seperation of variable question.

#10 2008-04-15 14:08:38

Re: Seperation of variable question.

#11 2008-04-15 14:12:22

Re: Seperation of variable question.

#12 2008-04-15 14:35:40

Re: Seperation of variable question.

#13 2008-04-15 14:46:08

Re: Seperation of variable question.

#14 2008-04-15 16:19:08

Re: Seperation of variable question.

#15 2008-04-15 16:22:11

Re: Seperation of variable question.

#16 2008-04-16 08:13:35

Re: Seperation of variable question.

#17 2008-04-16 08:55:54

Re: Seperation of variable question.

#18 2008-04-16 14:29:55

Re: Seperation of variable question.

#19 2008-04-17 06:16:02

Re: Seperation of variable question.

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