I'm trying to use a the symbolic solve function to rearrange an equation and solve for a variable, but I'm having trouble because the answer is a vector with units.
Example: given the area of a circle, find the radius. I enter:
A:= 3.14 cm^2
(A = pi * r^2) solve,r->
and it spits out a column vector (displayed here as a row vector)... -> (1cm, -1cm)
and I want to set that to another variable, say, R1, so I now have:
A:= 3.14 cm^2
R1:= [ (A = pi * r^2) solve,r-> (1cm, -1cm) ]
R1= (1cm, -1cm)
I know it can only be the positive value, so I want to pull that value out:
this gives me an error: R1 is red and the hover text reads "this value must be an array"
How can I set a variable to be the positive radius? (R= 1cm)
(I know I could just rearrange the equation here for the radius in the first place, but I want to keep it clear where I got the equation from. Also, this is just a simple example and I'd want to do it with something more complicated and want to avoid an algebra mistake)
Thank you very much!
(using Mathcad, version 126.96.36.199 [build 701291152] on windows7, 64bit)
Solved! Go to Solution.
thank you so much for your response. That is exactly what I was looking for BUT...
when I try the same thing you're doing, whether in the same document with different variables or in a new document, I still get an error. This time it's saying that my radius variable is undefined (with both methods).
I think I must be entering it wrong, although it looks the same as yours (from what I can see).
Any thoughts on what I'm doing differently? My file is attached.