# Thread: Calculus: Domain of a "box volume" equation

1. ## Calculus: Domain of a "box volume" equation

So the question gives me enough information to make an box volume equation dependent on a single variable... good: I can do calc with this. But the question asks: Determine the domain of the equation for this question...

Given that the piece of cardboard that this "net" was cut out of for a box, the cardboard was 10cm x 15cm, and my equation for volume was made with x's (I am confident on my equation at this point.. So assume that is right. I am just talking theory here). So the question is.... is my domain for this equation equal to the derivative, on the intervals where the derivative is positive? Or is it equal to the domain of V(x) where V(x) is positive? I am unsure :S

2. The domain of any function is the set of acceptable values for the variable. But you haven't said what that variable is so there is no way to know what values it could have. It is true that "volume" is must always be positive but I have no way of knowing what values your variable can have.

In general, there is no connection between between domain of a function and its derivative- if it has one- there exist functions that are not differentiable anywhere but they still have a domain.

3. Originally Posted by mike_302
So the question gives me enough information to make an box volume equation dependent on a single variable... good: I can do calc with this. But the question asks: Determine the domain of the equation for this question...

Given that the piece of cardboard that this "net" was cut out of for a box, the cardboard was 10cm x 15cm, and my equation for volume was made with x's (I am confident on my equation at this point.. So assume that is right. I am just talking theory here). So the question is.... is my domain for this equation equal to the derivative, on the intervals where the derivative is positive? Or is it equal to the domain of V(x) where V(x) is positive? I am unsure :S
Can you cut any less than 0cm or any more than 10cm?

Surely the domain must therefore be $\displaystyle 0 \leq x \leq 10$...