A simple problem wich worked fin in Prime 6 and doesnt in Prime 7.
In the first line, a simple equation is solved (it's a linear equation!) - all works fine ...
Then some constants where defined and a equation of the same type is to be solved => won't work, after a very long time there is some message, that there is not enough memory (again, to solve a linear equation!!).
If one first calculates the left side of the equation, it works ....
Whats wrong here? Prime error or mine .....
In general it works better to reverse the process. First solve the equation, then fill in the numbers:
Note that Prime symbolics doesn't normally work with units...
Success!
Luc
@ptc-1739038 wrote:
A simple problem wich worked fin in Prime 6 and doesnt in Prime 7.
No, thats wrong. What you tried doesn't work in Prime 6 either!
Main reason is that the unit deg is only known to the numeric, but not to the symbolic engine.
You may (re)define "deg" yourself to make it known to the symbolics,too, and what you tried to do will work OK
!!!BUT ..... what you did is a mathematical and pedagogical disaster! An absolute no-go! The same applies as Luc already said to your approach of adding a unit to an already defined variable. Never do so!
You define an angle to be 85.2 but you mean 85.2 °!! Thats a big difference! Defining alpha to be 85.2 means it to be 85.2 radian per definition.
So the correct way sure is to define the variables with their correct units and while you are doing this you may also assign a unit to l which obviously should be a length:
You may also use the numeric "root" function or a (numeric) solve block to find x, but what was said concerning variables and units still applies here, too, of course.
" ..... what you did is a mathematical and pedagogical disaster! "
Nice forum, one ask for help and gets insulted ... but the joke is on you, this is the work of a student, so basically you shamed a 15 year old. Kudos.
"No, thats wrong. What you tried doesn't work in Prime 6 either!"
I think it has, and most of the time it works in Prime 7 to. I think thats why they used it in the first example. Here a working one
And how a missing unit can cause the symbolic engine into an "Memory Overflow Error" is strange ...
The "solution" with all the units doesnt work here either:
What a the correct setttings here:
I tried it with units on and units off in symbolic math -> no change in behavior ...
@ptc-1739038 wrote:
" ..... what you did is a mathematical and pedagogical disaster! "
Nice forum, one ask for help and gets insulted ... but the joke is on you, this is the work of a student, so basically you shamed a 15 year old. Kudos.
I had no intention of insulting anyone and I don't see that anyone would have been insulted. You were told that you did something wrong and up to your last post we had to assume that is was your own attempt as a teacher you was showing. Furthermore you were told how to do it better.
I agree that the error of the symbolic engine is rather strange and should not pop up even if you setup the calc as you (or your pupil) did initially.
And concerning your follow up posting, I also can't see why and how the approach with the attached units fails at your side - but then, its hard to debug just a picture. It may help if you attach the worksheet.
Find attached a worksheet with a working version of the problem (at least it works for me in Prime 5 and Prime 6 - I have no P7 installed)
@ptc-1739038 wrote:
"No, thats wrong. What you tried doesn't work in Prime 6 either!"
I think it has, and most of the time it works in Prime 7 to. I think thats why they used it in the first example. Here a working one
And how a missing unit can cause the symbolic engine into an "Memory Overflow Error" is strange ...
I'll second Werner's request for you to please post a complete worksheet. It's often difficult, if not impossible, to look at a problem from just the picture, especially when not all of the variables are defined and the low resolution makes it difficult to interpret symbols (even when zoomed). Pictures are very useful but they don't tell the whole story.
Stuart
@ValeryOchkov wrote:
Yes, thats what Luc suggested in his first reply to solve the equation symbolically. But to make it useful to get a numeric result later it would mean that you have to turn it in a function of three arguments and this idea was rejected by the OP because he felt that this approach would not be appropriate for his students/pupils.
Sure the symbolic SHOULD be able to provide a solution for this simple equation even when the variables are already assigned values and even with the approach which was posted initially (adding the degree "unit" to the variable in the equation). For reasons I can't explain the symbolic sometimes chokes on this equation and while playing around (in Prime 6) I also experienced the problem that the symbolic will run "endless" without returning an solution. I would call it a strange bug (and it has nothing to do with the new symbolic engine, it also happened when I used the legacy engine).
