## Using Angle Units...

The angle unit of the SI system is rad and its dimension is 1. In engineering angles are often scaled in degrees. Maple supports the unit "deg" or "arcdeg". However when calculating with these units it does not convert deg to rad automatically and replace rad by 1. Here is an example:

The result of evalf(B) should be 15.708 (= 5*pi), i.e. a value without dimension, neither arcdeg nor rad. How do I get the correct result?

## Angle larger as 180 degrees...

For a question for my students I want them to calculate tge resulting vector from two vectors. The student had to answer by giving the length and angle of the resulting vector.

For the question the vector angle is always larger as 180 derges, the student should for example give a result of 270 degrees.

Currently I'm using the following code:

\$F1=100;#range(200,500,20);
\$F2=100;#range(100,200,10);
\$A1=45;#range(10,80,5);
\$A2=45;#range(10,80,5);
\$A1r=180+\$A1;
\$A2r=360-\$A2;
\$F1x=maple("cos((\$A1r)*Pi/180)*\$F1");
\$F1y=maple("sin((\$A1r)*Pi/180)*\$F1");
\$F2x=maple("cos((\$A2r)*Pi/180)*\$F2");
\$F2y=maple("sin((\$A2r)*Pi/180)*\$F2");
\$V1=maple("Vector(2,[(\$F1x),(\$F1y)])");
\$V2=maple("Vector(2,[(\$F2x),(\$F2y)])");
\$V3=maple("(\$V1)+(\$V2)");
\$F3=maple("LinearAlgebra[Norm](\$V3)");
\$V0x=maple("Vector(2,[1,0])");
\$A3=maple("LinearAlgebra[VectorAngle]((\$V0x),(\$V3))");
\$A4=maple("evalf(((\$A3)*180/(Pi)))");

As you can see maple will always give an angle smaller than 180 degrees since the angle between two vectors is always 180 degrees or smaller.

Can anyone tell me how I should code this problem such that the rest for A4 will be 270 degrees rather than 90 degrees, as is given from the current way of coding.

## How to put degree symbol on tickmark?...

Suppose that I have a plot:

`plot(sin((1/180)*Pi*x), x = -180 .. 180)`

I want to add a degree symbol after the tickmarks on the x-axis.  One approach which seem promising is to add a plot option for the x-axis:

axis[1] = [tickmarks = [90 = typeset("90", degree)]]

where "degree" is replaced by a code for the degree symbol. Maple is helpful here because I can point and click using the Common Symbols palette and insert a degree symbol. However this does not work delivering an error "Error, invalid neutral operator". This error is undocumented.

I can insert a Pi or an infinity symbol. If I want to I can put a degree sysmbol into ther title, but apparently not on the axes.

## How to solve this equation?...

Hello!

If I type this into a CAS calculator from Texas, I get the right result for Uc wich is 545.2.

solve(Uc&angle;-90=400&angle;X-150&angle;0+j*174.4,Uc,X)

This is used in AC circuits.

However, in Maple I'm using polar coordinates, so Im using this preamble:

phasor := proc (r, theta) options operator, arrow; r*cos(convert(theta*degrees, radians))+I*r*sin(convert(theta*degrees, radians)) end proc

This basically means that I can write phasor(value,angle in degrees) and get the lenth and angle of a vector on the complex plane.

Basically I want to know how I can make Maple solve this:

evalf(solve({phasor(U__C, -90) = phasor(400, X)-phasor(150, 0)+phasor(174.4, 90)}, {Uc, X})) Where I'm just interested in U_C , X doesn't matter.

I can't figure out how to do this with my current preamble. Does anyone know how to make this work?

## How to plot 2-D arrows using length and angle?...

Hello!

Vectors are defined by a lenth and an angle.

The arrow command wants me to give it a starting point and an endpoint in coordinates, for example:

with(LinearAlgebra);

with(plots);

gu := arrow([5, 10], [15, 20], .2, .4, .1, color = green)

I'm dealing with vectors from electrical circuits, so the information I have would be the lenth of the vector, and an angle given in degrees (which I could convert to radians if needed for the plot).

The goal is to plot all the vectors in the circuit on the same display so that it can be seen how they are in relation to each other, and to visualise the solution. This means I would need to find out the endpoint of the arrows to start the next arrow at that location with its angle in reference to the same axis. Does it make sence? I'm not sure about the wording of this.

Here's a picture of a calculated vector lenth and angle: http://imgur.com/hJtNeGg

So, the -45 degrees would need to be in reference to the y-axis for example, then the next vector can be placed at lets say perpendicular in reference to the vector sol_1, starting at its endpoint.

The only other way I have to draw this, excluding doing it by hand, is using the object tools from microsoft word, and to be honset I dislike using word for math stuff. I would much rather learn the syntax for Maple to do this.

I hope someone knows what I mean, Please ask if somethig is unclear,

Thanks!

## electrical circuit calculations with polar coordin...

Below is a calculation with 200 Volt and 100 Ω.
The output is 1 Ampere at -45 degrees.
This is useful for electrical circuit calculations, and I can get the right result on a TI-nspire.

However I can't make maple 2015 do it. It's resembling polar coordinates but I can't seem to find any info I can understand.

"((200&angle;0&deg;))/((100&angle;45&deg;)+(100&angle;45&deg;))=\

1&angle;-45&deg;"

below is the same equation but in a picture so it can be read by humans:

http://imgur.com/3i2Su0B

Hopefully theres some simple comands that can help make this easy.

Thanks

## Heavy handling with complex numbers in modulus-arg...

Dear Maple users

An engineering student asked me how Maple is handling complex numbers in polar form. He told me that his fellow students are using another CAS, whereas he himself prefer Maple. When making calculations with AC currents having different phases the other students were using the easy notation depicted in the first line on the picture below. Obviously here the angle (argument) is measured in degrees. I tried to perform the same calculations in Maple, but found it to require a very heavy notation: the other three lines on the picture. Now my question is: Does it really have to be that messy, or maybe there are some package, which will accomplish the task in a more neat way? I mean it is a rather common operation in the engineering sciences.

NB! Of couse one can argue about the educational value of using the notation of the other CAS! From that viewpoint they will probably not learn anything ...

Regards,

Erik

## Using angular units with trig functions...

I'm looking at Maple as a possible alternative to Mathcad (which I've been using for years, but is now very jaded compared to other options like Maple and Mathematica).  I'm a civil engineer and for what I do, one of the better features of Mathcad is the way it handles units.  For example, if I specify an angle in degrees (say phi=30 degrees) and then ask for sin(phi), I get 0.5.  At face value, I though Maple would do the same kind of thing.  However, this doesn't appear to be the case (see attached worksheet).  The only workaround that I can see is to specify the angle in degrees (but without assigning ) and then multiply the specified value by pi/180 (to convert to radians) before passing it to the sin function.  Which is all a bit messy and not at all an attractive solution.

Am I misunderstanding the way units work in Maple and is there a clean way of specifying angles in degrees (which is what engineers work with) and using these values directy in trig functions?

Thanks in anticipation,

Ian

## Visualization of "Clock and Degrees" problem

by:

Clock:=proc(H, M)  # H and M - time in hours (0 <= H <= 23) and minutes (0<=M<60)

local A1,A2, A, B, B1, C1, C, E, F,alpha,t, T, T1, T2, P, G;

uses plottools, plots;

A1:=(irem(H,12)+M/60)*30;  A2:=M*6;

A:=circle([0,0], thickness=5);

P:=disk([0,0], 1, color=grey);

## Maple for "Clock and Degrees" problem

by: Maple

Here are two procedures associated with a clock with hands. I think they are interesting not only for fun, but will be useful for teachers in schools in the preparation of such tasks.

The first procedure called  ClockHandsAngle  finds the angle between the hands of the clock at any time.

The second procedure called  TimeFromAngle , for a given angle finds all times in a given time range. The first procedure  is...

## Trig Packages for Maple 15- MAC...

I have a problem with inputting a new package in my version of maple (15) for mac. The packes makes it possible to do calculations with cos/sin/tan in degrees instead of radians. I need to use this for my Engeneering studies in Denmark.

In pc you just place the package in the labrary subfolder under the Maple 15 folder, but i can't find that subfolder anywhere on my mac??
Where should i put the package to make it work?

I have 2 files; "Trig.ind" and "Trig.lib" - whichone to use?

## Slider in degrees...

Hi!

Probably trivial, ...but how to set up a slider in degrees.
I'd like to use degrees instead radians in expresion ...from some reasons.
Help will be apreciated :-)

wzelik

slider.mw

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