Minimization work frame of a cube

I have a cube with W x D x H dimension. Each meter of W cost $20, D cost $30 and H cost $50. Cube must have at least 600 m^3 in volume. Formulate design optimization problem.

This is my first time using MatLab, so please explain to me really clearly. I really need help with this problem. Thank you before and in advance.

Answer 1

[Walter Roberson]

For cubes, W, H, and D must all be equal. If we call that one value x, then the cost for the cube is $20*x + $30*x + $50*x = $100 * x. The volume of the cube must be at least 600. The volume of a cube with edge x is x^3, so we have x^3 = 600, so you only need to solve x^3 = 600 for x and multiply by $100 to get the cost

[Rudi Gunawan]

sorry, I mean cuboid, not a cube

[Walter Roberson]

What tools are you allowed to use?

[Walter Roberson]

This can be done without difficulty with an fminsearch() on an anonymous function of two variables. Or it can be done by noting that the sides are going to be in ratio so that each one contributes equally to the cost.

[Rudi Gunawan]

i can use any tools in matlab. please tell me the coding composition, i really new in matlab thanks