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# differential equations watch

1. i am stuck on these differential equations. please can someone solve them? thanks

1. dx/dt + 3x = e^-t where x=0 when t=0

2. dy/dt + y/t = e^-t/10

3. x (with a dot over it, whatever that means) = e^(x+t) where x(0)=0

4. y'(x) = -y^4 * x^3/2

thanks once again
2. You've done integrating factor? Oh and x with a dot over it means dx/dt
3. (Original post by Ewan)
You've done integrating factor? Oh and x with a dot over it means dx/dt

sorry mate, you aint helped me at all.
4. (Original post by wrooru)

sorry mate, you aint helped me at all.
Well thats how you would do it, search the internet for integrating factor. They aren't variable separable which I guess is the method you know.
5. (Original post by Ewan)
Well thats how you would do it, search the internet for integrating factor. They aren't variable separable which I guess is the method you know.
did you negative reputation me on this post?
6. For (3), e^(x+t) = e^x*e^t, which is now separable.

(4) is separable too.
7. (Original post by wrooru)
did you negative reputation me on this post?
Huh? No I didn't give you neg rep if that's what your asking.

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