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These are questions asked by wswain

Good Morning,

I don't know why I have such difficulties with rotational units, esp the 2*pi conversions with radians and revolutions. 

   We are often back solving from MPH of the vehicle back to RPM of the wheel (revolutions per minute [or seconds]) to Rad/sec for engineering units such as torque*RPM calcs for power - kW.   

Almost everytime I try to use units to convert the units the worksheet will revert to "atomic" units.   I quote "atomic" as this is what I appears to be.:  See graphic (also simplifiied worksheet attached)

The unit length(radius) seems to be a factor that is not well documented.   It also seems the earlier rplies include extra work to use convert and possibly "symbolic = true") as an extra step per Acer in an earlier posting several years ago.   

When running calcs the convert, or simplify (to cancel length units m and inches out) the cancelations and the unit combinations seem to work awkwardly in this particular area.


Good Morning,

    Can anyone explain how the Statistics:-nonlinearfit(Time Vector data points, weight at time t) can be used with a real time based (with units) set of vectors?

    To get the fit for an equation to data of the form A*(1+B)^t   with t being time and the growth in kg/sec  the solver needed to be unitless and I get the coefficents.  Reapplying unit of time blows up the eqn.

   P.S., I think I'm being math obtuse this morning on the units.



I have read a few papers on accuracy and numerical methods to solve problems.  My personal interest is in very stiff DAE equations of state (eos) for gaseous expansions/flow problems in very high differential starting conditions for the convergence to occur in the initial time steps.

A long time goal has been to convert the FORTRAN real*16 floating point DAE solver (initially ran on CRAY) into Maple proc() using arbitrary precision that actually solves at the hardware float ieee precision.

Any reference material on stiff solvers and maple implementation would be great.


Does anyone use maple calculator?


I am trying to use it on my iPad for matrix functions.


I tried standard maple %T for transpose, get an error.  I've tried -1.  No joy.  

I can't seem to find how to assign to a variable, or use indexing to a matrix element.


Any suggestions welcomed for iPad maple functionality. 

Is there a reason that an angle theta from zero to pi/2 (0 to 90 deg) returns as invalid for an animation range?  I am trying to rotate a vector 2D for visualization.  This is build-up towards a 3d rotating vector in an animation.  


Here is the code: theta is the arrow tip rotation's location via cos(theta), sin(theta) coordinates in a 2D vector.


animate(arrow, [<cos(theta), sin(theta)>, width = [0.05, relative], view = [-1 .. 2, -1 .. 2], color = "blue"], theta = 0 .. Pi/2)



Error, (in plots/animate) 0 = 0 .. (1/2)*Pi  is an invalid animation range



Thanks In Advance,


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