Hi Vetri,
I've moved this to the MATHCAD Community.
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Re: this value must be a function but has the form unitless mathcad
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Re: this value must be a function but has the form unitless mathcad
an and bn need to be made functions of v.
n, in the ode solve block, needs to be a function of t.
See attached.
Alan
Edited to add an extra comment in the attached workfile.
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Re: Very slow worksheet - any limitation of program size?
Werner Exinger wrote:
Your program out(data,...) stretches over 21 pages and is handled as sort of a unit when edited.
One good rule - one function-program must be not bigger than one screen.
Or go to http://communities.ptc.com/groups/mathcad-paradoxes
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Re: Units in the rkfixed function
HARVEY HENSLEY wrote:
Valery,
The other solvers will probably work with units in a semi-fashion
Harvey
Thanks Harvey.
I know it very well. The life in Russia is in semi-fashion too. Not only now 
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Input logarithms with a fractional base
Probably newbie question
Is it possible to input logarithms with a fractional base? When I try it creates a rational expression. Parentheses don't work either. Or, must I change the base?
Thanks
Joe
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Re: Input logarithms with a fractional base
Hi Joseph,
One example of a logarithm with a fractional base is the natural logarithm ln(x), with base 2.71828182845....
A logarithm of a value x (> 0) to any base b (> 0) can be computed as ln(x)/ln(b).
Or do you mean something else...?
Luc
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Re: Input logarithms with a fractional base
Joseph Stavitsky wrote:
Probably newbie question
Is it possible to input logarithms with a fractional base?
Yes, as long as the base is positive and does not not equal one.
When I try it creates a rational expression.
What do you mean by that and why do you think thats not as it should be?
Parentheses don't work either. Or, must I change the base?
You don't show what you do and don't say what you expect, so we can't tell. Obviously when you want the logarithm of a base unequal to 10 you have to state that.
You know that in Mathcad log(a) means the logarithm of a to base 10, while log(a,b) ist the logarithm to base b of a.
If you want to take the logarithm of base 2/3 from an argument like 27/8 (which is obviously -3), you would type log(27/8, 2/3)=
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Re: Input logarithms with a fractional base
That last part is what I was missing, thanks. I was trying to input it as it is traditionally typeset.
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Re: Input logarithms with a fractional base
LucMeekes wrote:
Hi Joseph,
One example of a logarithm with a fractional base is the natural logarithm ln(x), with base 2.71828182845....
A logarithm of a value x (> 0) to any base b (> 0) can be computed as ln(x)/ln(b).
Any base but b=1!
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MathCAD Prime 3.0 unit formatting
I am using an excel component with an output to define variables. The variables are then displayed in the worksheet. I am trying to define the units then and it keeps putting 1/m before the mm unit I am trying to specify.
See below:
What do I need to do in order to correct this?
Thanks,
Brad
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Re: MathCAD Prime 3.0 unit formatting
You have to redefine the variable using "Core_Depth:=Core_Depth*mm"
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Re: MathCAD Prime 3.0 unit formatting
That is what it was.
Thanks,
Brad
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Re: Matrices conundrum
Yea sorry, i its quite difficult to explain my thought train, expecially when i am not familiar with these programs or how to explain in the right terminology.
I've insered images of the excel doc where I originally attempted to solve this problem (not sure if i can attach a full .xlsx doument), hopefully this gives you an indication of what i am dealing with.
Selection of three flavours, one from each of the extruder lines so if i can somehow display the permutations/combinations* in a matracies then apply the function to this data to find the number of ingredients in each array, and then organise these to see which have the highest number of ingredients.
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Re: Matrices conundrum
James Butler wrote:
Yea sorry, i its quite difficult to explain my thought train, expecially when i am not familiar with these programs or how to explain in the right terminology.
Just try normal math terminology.
I've insered images of the excel doc where I originally attempted to solve this problem (not sure if i can attach a full .xlsx doument),
You can, but I guess it won't help as motivation to look at hidden Excel cell formulas is rather low, especially as you write that this is not the solution of your problem (we still don't know what problem) but just a partial attempt.
hopefully this gives you an indication of what i am dealing with.
Unfortunately not. You haven't answered a single of the (implicit or explicit) questions.
Selection of three flavours, one from each of the extruder lines s
What do you know about the flavors available. Is the distribution of the 25 flavours to the three extruders known? If yes, we would have just 240 possible set of three flavors. You have to clearly state the problem, the condition and assumptions first. Again setting up a worksheet with variables, vectors or matrices to give us an idea of what information can be assumed as "given" may help. Then we can look for what you are trying to find out.
so if i can somehow display the permutations/combinations* in a matracies then apply the function to this data to find the number of ingredients in each array, and then organise these to see which have the highest number of ingredients.
Again, what kind of permutations/combinations? In what way you would like the result displayed im matrices (meaning of rows, columns and elelement value)? What function?
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matrix dilemma
The attached sheet poses a question about matrix math; I'm a bit confused apparently about multplying vectors and matrices. The symbolic math seems to indicate that I should get the same answer with either method, but the numeric application shows clear differences larger than rounding errors should allow.
What am I missing??
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Re: matrix dilemma
You simply forgot to transpose MAT in the first numerical case!
Alan
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Re: matrix dilemma
Duh!
Thanks for putting up with silly mistakes!
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Re: Matrices conundrum
I'm not sure I fully understand, but, in Mathcad-speak, there are combin(25,8) = 1081575 ways of choosing 8 from 25 flavourings to send to A. For each of these there are combin(17,15) = 136 ways of choosing 15 from the remaining 17 flavourings to send to B (the remaining two go to C). In total therefore there are 1081575*136 = 147094200 combinations to be condsidered. That's a lot to tabulate!
Alan
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Re: matrix dilemma
We all make them!
Alan
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Re: Matrices conundrum
Ok, lets break this problem down, the image below shows the 25 flavourings, both beef and chicken on EXtruder 3, 14 flavours on 2 and 9 on EX 1. Am i correct at saying there are 252 combinations? If so is there a way of showing it in a 3D matrix?
Now each of these flavours comprises of a set ingredients, and I want to find a way of relating functions to the '252' combinations, so that I don't have to have to assess them individually.
Tbh if this doesn't make sense now I think I'm out of my depths and I should probably brush up on my maths before I take it any further. But thanks for your input, its been a great help in knowing my limitations 
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