# Second order differential equations

1. May 14, 2012

### fan_boy17

1. The problem statement, all variables and given/known data

finding the general solution. I would like to know if the 20-e^x will be treated as a sum of a polynomial?

2. Relevant equations

3. The attempt at a solution

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2. May 14, 2012

### Staff: Mentor

20 - ex is not a polynomial. A search on wikipedia will turn up the definition of a polynomial.

3. May 14, 2012

### HallsofIvy

Staff Emeritus
It is, of course, the sum of two functions. Did you really mean to say "polynomial"?

You should look for a "particular solution" of the form A+ Bex.

4. May 14, 2012

### LCKurtz

That's a typo, Halls meant $A+Be^{2x}$.

5. May 15, 2012

### fan_boy17

can anyone help with solving it :(

6. May 15, 2012

### LCKurtz

What are you stuck on? Have you solved the associated homogeneous equation for its general solution $y_c$? Have you tried looking for a particular solution of the NH equation of the form $y_p=A + Be^{2x}$ as has been suggested? It is all straightforward. Show us what you have so far.