New in MathCAD Prime - problems with simple calculation (solve function)

[hxaver]

Hi all,

I want to get some knowledge about MathCAD Prime and for better understanding I made some simple calculations.

I have done a simple example to get familiar with MathCAD solving functions.

I want to calculate the charging time of a capacitor for two different voltage thresholds.

have attached a pdf file of my MathCAD sheet.

What I have done in MathCAD delivers the right results but the intermediate steps are wrong.

Can someone explain me what I have done wrong?

Thank you for your help!

[AlvaroDíaz]

Hi.

Mathcad is like matlab: for numerical calculus. So, they dislike undefined variables. To avoid 'the red' you can use undefined variables as function parameters, like in the attached.

Best regards.

Alvaro.

[BB1]

Can we use the variable in Matrix and solve them like AX=B, if all matrix is having the variables only no constants, can we solve those kind of matrix in Mathcad prime.

[Werner_E]

You may consider opening a new thread and attach a worksheet which shows a specific exemple of what you are looking for.

[Fred_Kohlhepp]

Which intermediate steps are wrong?

You have used variable names without having assigned numeric values to them first; the red outlines are the numeric processor complaining about that.  There is no assigned value for , and the numeric processor is complaining.  But that line is defining the variable "Calculation" to be the result of a symbolic solution.  If you had typed:

instead of the third line, you would have created a function to calculate the time.  And then solved for your times.

[-MFra-]

My solution: