- #1

- 516

- 11

You are using an out of date browser. It may not display this or other websites correctly.

You should upgrade or use an alternative browser.

You should upgrade or use an alternative browser.

- Thread starter jaydnul
- Start date

- #1

- 516

- 11

- #2

mfb

Mentor

- 35,395

- 11,753

And there are functions of multiple variables where the order of differentiation matters.

I don't think I ever had that problem with physics-related equations.

- #3

- 329

- 34

Let y = f(x). Your equation dy/dx = y can be rewritten in this notation as f'(x) = f(x). This gives us f'(x)/f(x) = 1. Integrating

log f(x) = x + c

log y = x + c and so

[tex]y = Ae^x [/tex]

The chain rule comes in when you observe that [tex]\frac{d}{dx}logf(x) = f'(x)/f(x))[/tex].

So the general answer about when you can split dy and dx and treat dy/dx as a fraction is that it is justified when it is a shortcut way to use the chain rule.

- #4

- 516

- 11

Wow great point. That really helps alot

Share: