# What is this equation called?

1. Jun 20, 2013

### Goethe10

Hello everybody, What is this equation called? I'm from non-English speaking country and I need to look up materials about how to solve it, Thank you.

2. Jun 20, 2013

### tiny-tim

Welcome to PF!

Hello Goethe10! Welcome to PF!
(why have you written a "d" there? )

This is an ordinary equation,

and the four possible answers are dervatives of it,

except that instead of writing dy/dx = f(x), they've written them dy = f(x)dx

3. Jun 20, 2013

### Goethe10

Haha, sorry.
It was just smudge done by paint tool, not an actual D, sorry about confusion :P
What do you mean "ordinary equation" Can you please give me the full name? Thanks.

4. Jun 20, 2013

### tiny-tim

i mean it's just an equation, there's nothing special about, there's nothing to look up!

(just differentiate it!!)

5. Jun 20, 2013

### Goethe10

Ah, I see! :D Thank you
So
3+2x^3 would be
6x^2
Can you please tell me what does "dy" means?

6. Jun 20, 2013

### tiny-tim

correct!
if you'd written the equations in full, you would have written:

y = 3+2x3

So dy/dx = 6x2

The "dy" and "dx" in "dy = 6x2dx" are called differentials (or infinitesimal differentials).

You can always rewrite any dy/dx equation so that the dy and dx are on opposite sides …

look that up in almost any book on calculus

7. Jun 21, 2013

### Goethe10

Thank you! :)