# Is this valid?

1. Sep 11, 2010

### RandomGuy88

I am wondering if this is valid.

(de/dx) + (1/p)(dP/dx) = (1/dx)(de +(1/p)dP)

Basically are you allowed to pull a 1/dx out of the equation?

2. Sep 11, 2010

### l'Hôpital

What would 1/dx even mean?

3. Sep 12, 2010

### Pengwuino

Yes it is possible, although a mathematician would not like it . There are certain requirements the function must meet before you are allowed to treat the differentials like parts of a fraction which I don't know off the top of my head.

4. Sep 12, 2010

### RandomGuy88

Thanks for the replies. I am not sure what 1/dx would mean. In fact that is why I am asking this question, because I didn't think it would mean anything and therefore is wrong.

5. Sep 12, 2010

### Pengwuino

Let's say I have $${df \over dt} = 3t^2$$ and you just pulled out the 1/dt to get $${1 \over {dt}}(df) = 3t^2$$. There is nothing special going on.

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