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gkokovidis

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20 years, 287 days
Draeger Medical Systems, Inc.
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Regards,
Georgios Kokovidis
Dräger Medical

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These are answers submitted by gkokovidis

How to find exact value of it?...

gkokovidis 2370
December 16 2015
0 1

If Maple cannot "simplify" or convert to an exact value, without manual intervention, you can try using the identify command.

> 

restart:Digits:=20:
> 

(-2*sqrt(7)-4)*EllipticK((1/8)*sqrt(2)*(-3+sqrt(7)))^2+4*EllipticE(-(1/8)*sqrt(2)*(-3+sqrt(7)))*sqrt(7)*EllipticK((1/8)*sqrt(2)*(-3+sqrt(7)));

(-2*7^(1/2)-4)*EllipticK((1/8)*2^(1/2)*(-3+7^(1/2)))^2+4*EllipticE((1/8)*2^(1/2)*(-3+7^(1/2)))*7^(1/2)*EllipticK((1/8)*2^(1/2)*(-3+7^(1/2)))

 (1)
> 

evalf(%);

3.141592653589793239    

(2)
> 

identify(%);

Pi

                                                       (3)
> 

 

Download identify.mw

See ?identify for more help on this.

 

 

Regards,

Georgios Kokovidis

Dräger Medical

First ten fractions of pi...

gkokovidis 2370
December 13 2015
1 1

restart:with(numtheory):

a:= cfrac(Pi);

seq(nthconver(a,i),i=1..10);

You have to load the numtheory package, or use the short form of the command.  Look at the examples that were provided to you from your previous post, that used cfrac.

 

Regards,

Georgios

 

repeated part of a fraction...

gkokovidis 2370
December 13 2015
1 2

cfrac looks like the right command for your problem.

> 

restart:with(numtheory):
> 

cfrac(3/11+3*sqrt(3),50,'quotients');

[5, 2, 7, 1, 1, 6, 1, 627, 1, 6, 1, 1, 7, 2, 9, 1, 12, 16, 1, 10, 1, 4, 3, 1, 1, 2, 1, 14, 2, 3, 10, 9, 1, 1, 139, 5, 5, 3, 2, 3, 6, 1, 1, 1, 9, 1, 2, 1, 6, 1, 2, `...`]

 (1)
> 

 

Download cfrac.mw

 

Regards,

Georgios

How do i plot a curve using a parametric...

gkokovidis 2370
November 11 2015
1 0

See example here:

http://www.maplesoft.com/support/help/Maple/view.aspx?path=plot/parametric

 

Regards,

Georgios Kokovidis

Dräger Medical

How to use above value?...

gkokovidis 2370
November 11 2015
2 5

ans:=solve({alpha = (1/2)*lambda*alpha*Pi, beta = (1/2)*lambda*beta*Pi}, lambda);

eval(lambda^6,ans);

Regards,

Georgios

Testing the speed of a procedure...

gkokovidis 2370
November 07 2015
0 1

See the help file for time.  ?time at the command prompt.  Typical usage below.

st := time():
... statements to be timed ...:
time() - st;

Regards,

Georgios

The equivalent of pcolor from matlab in ...

gkokovidis 2370
November 01 2015
1 1

See the Maple help page below.

http://www.maplesoft.com/support/help/maple/view.aspx?path=plots%2Fsurfdata

The surfdata command with the option dimension=2 looks similar to what the Matlab help page

for pcolor describes.

 

Regards,

Georgios

How to know what x and y should be...

gkokovidis 2370
November 01 2015
0 0

Without limits, Maple will default to -10..10 for x.  Try it and see.  The range of x depends on what part of the function you are interested in viewing.  Pick your range accordingly.  Start with the default, and then modify the range to meet your requirements.  If  you do not have requirements, then you might choose to settle for the default.

> 

restart:
> 

plot(-x^3+2*x+1/4,x);

 
> 

plot(-x^3+2*x+1/4,x=0..3);

 
> 

plot(-x^3+2*x+1/4,x=-6..-1);

 
> 

 

Download plot.mw

 

Regards,

Georgios

Points on the curve...

gkokovidis 2370
October 25 2015
0 1

You can ue display, part of the plots package, to combine more than one plot.

> 

restart:with(plots):
> 

f:=x->x^2;

proc (x) options operator, arrow; x^2 end proc

                                                                                                                                                                                    (1)
> 

p1:=plot(f,-3..3):
> 

p2:=pointplot([[1,1],[2,4]],color=[red,blue],symbol=circle,symbolsize=25):
> 

display(p1,p2);

 
> 

 

Download plotwithpoints.mw

Regards,

Georgios

Quick and dirty part 2...

gkokovidis 2370
October 17 2015
2 0

Here is one more option, using Roots, from the Student[Calculus1] package.

restart:with(Student[Calculus1]):
f:=x->(7-x)*sin(x^2-7);
f1:=D(f);
Roots(f1(x), -2.4 .. 2.4, numeric);
                 [-2.334981494, -1.525138568, -0.06124071559, 1.492263788, 2.320169646]

Regards,

Georgios

How to sketch secant lines on curve?...

gkokovidis 2370
October 12 2015
1 0

One more option is to use the built in tutor.  It will display the function, the secant lines (as many as you select, as well as an animation, similar to what is shown by Tom Leslie.

Student[Calculus1][TangentSecantTutor]();

This can be found under Tools-Tutors-Calculus-SingleVariable-Secants...

 

Regards,

Georgios Kokovidis

Dräger Medical

Funtion Plot...

gkokovidis 2370
September 26 2015
0 1

Here is one way, building on the solution from your previous question..


> 

restart:
> 

f:=x->80*x-2*x^2;

proc (x) options operator, arrow; 80*x-2*x^2 end proc

                                                                                                        (1)
> 

plot(f);

 
> 

Aprime:=diff(f(x),x);

-4*x+80               

                                               (2)
> 

solve(Aprime=0,x);

20                                                                         

(3)
> 

 

Download PlotFunc.mw

Regards,

Georgios Kokovidis

Dräger Medical

Why can't Maple calculate it?...

gkokovidis 2370
September 15 2015
0 2

Looks like you are missing a multiplication sign before the 'x' and before the 'x^4'.  Try it and see what happens.

Edit:  I was wrong.  See replies below.

Regards,

Georgios

Example Worksheet...

gkokovidis 2370
September 08 2015
3 0

I created this worksheet a while ago to do what the OP is asking.  The spice netlist at the end of the worksheet is a sanity check.  It can be run with LTspice, which is available for free.

> 

restart:Digits:=20:
> 

 

Add two AC waveforms:  For example 150<80 and -10<-260

> 

 

First, define the magnitude(s). .

> 

mag1:=150;

150

 (1)
> 

mag2:=-10;

-10

 (2)

Define each of the angles.  For the example below, the 1st angle is -90 and the second angle is -180.

> 

ang1:=evalf(convert(80*degrees,radians));

1.3962634015954636615

 (3)
> 

ang2:=evalf(convert(-260*degrees,radians));

-4.5378560551852568999

 (4)
> 

 

Convert from polar to rectangular for each of the magnitude,angle pairs.

> 

p2r1:=[mag1*cos(ang1),mag1*sin(ang1)];

[26.047226650039552334, 147.72116295183120890]

 (5)
> 

p2r2:=[mag2*cos(ang2),mag2*sin(ang2)];

[1.7364817766693034895, -9.8480775301220805935]

 (6)
> 

 

> 

 

Add the two together.

> 

sum_mags:=p2r1+p2r2;

[27.783708426708855824, 137.87308542170912831]

 (7)

Magnitude.

> 

abs(sum_mags[1]+(sum_mags[2]*I));

140.64466622535770677

 (8)
> 

 

Angle, which gets converted to degreees.

> 

argument(sum_mags[1]+(sum_mags[2]*I)):
> 

evalf(convert(%,degrees));

78.606542061259769360*degrees

 (9)

ac voltage addition spice netlist example - phasor domain analysis
# linear analysis line: 100 point sweep from 60 to 60, therefore no plot window
# will show up.
 
v1 1 0 ac 150 80
v2 2 1 ac -10 -260
  
#v2 2 1 ac 12 35 sin     
#v3 3 2 ac 22 -64 sin
    
#v3 3 2 ac 0.001 0 sin
rdummy 3 2 0.01    
r1 3 0 10k      
.ac lin 100 60 60            
.print ac v(3,0) vp(3,0)
.end

 

       --- AC Analysis ---

frequency:        60        Hz
V(3):        mag:    140.645   phase:    78.6065°         voltage

 

Download phasor_voltage_addition_example.mw

Regards,

Georgios

Another option...

gkokovidis 2370
June 12 2015
0 0

One more way to complement what has been answered.

 

You can pass a floating point number to each of the commands.

ln(3.0)

exp(5.0)

The results will be the same as using evalf on an integer.

 

Regards,

Georgios Kokovidis

Dräger Medical

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