# Homework Help: Error, (in ODEtools/info) x(t) and x cannot both appear in the given ODE.

1. Sep 5, 2010

### Susanne217

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

Hi I am trying to solve a seperable differential equation in Maple

eqn1:=diff(x(t),t)=3*t^2/sqrt(x);

But every time I type

dsolve(eqn1,x(t));

I get the very hurtfull error from Maple

"Error, (in ODEtools/info) x(t) and x cannot both appear in the given ODE."

What am I doing wrong?

I have changed it to

eqn1:=diff(x(t),t)=3*t^2/sqrt(x(t)); and Mapple accepted it...

Is this right?

Last edited: Sep 5, 2010
2. Sep 5, 2010

### HallsofIvy

"x(t)" and "x" are different symbols. Maple is interpreting "x(t)" as a function of t and "x" as a constant. It appears to Maple that you are using "x" in two different ways and it will not allow that.

3. Sep 5, 2010

### Susanne217

Okay why Hallsoftivy could they go ahead and write this in the error insteed :)

But thank you :)

I'm given the differential equation

$$\frac{dx}{dt} = \frac{3t^2}{\sqrt{x}}$$

without any initial conditions

the right way to solve this in Maple is the command:
eqn1:=diff(x(t),t)=3*t^2/sqrt(x(t));

??

Last edited: Sep 5, 2010
4. Sep 5, 2010

### HallsofIvy

??? That's what I just said: Maple is telling you that you cannot use the letter "x" in two different meanings and that is how Maple is interpreting what you gave.