Redefining variables to simplify equations

[zredey]

Hello!

I am faced with a math problem using a system of several inequations. A colleague suggested to use MathCAD´s numeric solver for the problem.

I am new to MathCAD and fell that I am making a silly mistake but I can not find what exactly.

I would like to simplify my equations by defining some values but this in turn will mess with the solver.

I have attached a very simple example of what I am trying to do.

Please tell me my silly mistake so I can move on to solve my real problem

Thank you!

[RichardJ · Accepted solution]

There needs to be an explicit relationship between R1 and R1.min. You have simply assigned constant values to two variables. The second assignment is defined in terms of the first, but it's still a constant value. Make R1.min a function of R1, then Find knows what to do.

[zredey]

Thank you for your answer! This linking of the variables was missing in my sheet. I had a feeling that I was somehow redefining constants but I did not know how else to do it.

I was aiming for simplifying my equations and although it most definitely helps to use notation like this escpecially if R1.min will be refined with other (for example temperature dependencies) later on, but having to write R1.min(R1) every time when I want to refer to R1.min is making my equations still quite big and unnecesarily complicated.

Thank you again for your answer it helped me a lot!