Any idea why I don't have any issue with the case below but get "x-not defined" error for the case above.

Thank you.

In the first case probably you might have a 0 at the denominator, try using the 4-arguments version of solve and set something slighty different from 0 in the solve boundaries.

Wrote

Any idea why I don't have any issue with the case below but get "x-not defined" error for the case above.

Observe the solve bloc how to escape x not defined

Page45.sm (26 KiB) downloaded 37 time(s).

Wrote

Wrote

Any idea why I don't have any issue with the case below but get "x-not defined" error for the case above.

Observe the solve bloc how to escape x not defined

Page45.sm (26 KiB) downloaded 37 time(s).

Thanks, Jean. This is a great help. However, I am still scratching my head to make the below function work.

f.c (x,y) is the compression stress at a point in an I-shaped concrete section using stress-strain curve for concrete by Popovics. I simplified it at given maximum strain.

x is the distance from the point to extreme compressive fiber
y is the distance from the neutral axis to extreme compressive fiber
maximum strain at the extreme compressive fiber is given.

Why can't I make g(y) work? Is this possible for smath to solve the equation g(y)- whatever = 0 (say sum of compression force in steel & concrete - tension force in steel - Axial force = 0)?


To make it a bit more complicated, if the maximum strain is unknown (say epsilon_c). And the section is under Axial P and Moment M. Can we solve the equations:
SUM of Axial = 0
SUM of Moment = 0

I'll create a real problem and post later but if you can take a look at the attached smath file and help me to solve the issue, it'd be much appreciated.Page45.sm (26 KiB) downloaded 20 time(s).

f.c(x;y) don't need length unit so I have removed units of y in integrals from g(y). ((y-x)/y is unitless)
It was all inches in integral so removed by dividing ft to in. Function worked.
Long word short, perhaps removing units temporarily is the key for your function.

Regards

Worksheet1.sm (7 KiB) downloaded 25 time(s).

Wrote

f.c(x;y) don't need length unit so I have removed units of y in integrals from g(y). ((y-x)/y is unitless)
It was all inches in integral so removed by dividing ft to in. Function worked.
Long word short, perhaps removing units temporarily is the key for your function.

Regards

Worksheet1.sm (7 KiB) downloaded 25 time(s).

Thank you very much. I copied and pasted your revised formula into my sheet and it worked like a charm. But when I edited it to match, it didn't work. I must have done something stupid somewhere.


Page45.sm (9 KiB) downloaded 27 time(s).

Wrote

...
Thank you very much. I copied and pasted your revised formula into my sheet and it worked like a charm. But when I edited it to match, it didn't work. I must have done something stupid somewhere.

Hi. Implicit parenthesis is a source of a lot of errors. And SMath isn't the only one that have this problem. Wolfram Mathematica, in traditional form have it too. But you can copy the expressions in SMath and paste it as text to see what happen:

g(y.1):78*'ft*int(f.c(x,y.1/'in),x,x.0/'in,y.0/'in)+92.25*'in*int(f.c(x,y.1/'in),x,x.1/'in,y.1/'in)

g(y.1):78*'ft*int(f.c(x,y.1/'in),x+92.25*'in*int(f.c(x,y.1/'in),x,x.1/'in,y.1/'in),x.0/'in,y.0/'in)

Also can show it:



This is: your differential it's wrong.

Best regards.
Alvaro.

The first solve issue was solved.
Next, maybe show something to illustrate the project ...

Wrote

Wrote

...
Thank you very much. I copied and pasted your revised formula into my sheet and it worked like a charm. But when I edited it to match, it didn't work. I must have done something stupid somewhere.

Hi. Implicit parenthesis is a source of a lot of errors. And SMath isn't the only one that have this problem. Wolfram Mathematica, in traditional form have it too. But you can copy the expressions in SMath and paste it as text to see what happen:

g(y.1):78*'ft*int(f.c(x,y.1/'in),x,x.0/'in,y.0/'in)+92.25*'in*int(f.c(x,y.1/'in),x,x.1/'in,y.1/'in)

g(y.1):78*'ft*int(f.c(x,y.1/'in),x+92.25*'in*int(f.c(x,y.1/'in),x,x.1/'in,y.1/'in),x.0/'in,y.0/'in)

Also can show it:



This is: your differential it's wrong.

Best regards.
Alvaro.

Wow, this is very tricky one. I believe this is the source of all issues I have had so far. How can I prevent this from happening? Thank you.