Advanced Search

rrbaldino

55 Reputation

4 Badges

11 years, 302 days
Contact rrbaldino

MaplePrimes Activity


These are questions asked by rrbaldino

laplace of Dirac derivative...

rrbaldino 55 Maple
derivative laplace inttrans
September 28 2018
1 8

restart;
with(inttrans);
[addtable, fourier, fouriercos, fouriersin, hankel, hilbert, 

  invfourier, invhilbert, invlaplace, invmellin, laplace, mellin, 

  savetable]
laplace((diff(Dirac(t), t))*cos(t), t, s);
                               0
int((diff(Dirac(t), t))*exp(-s*t)*cos(t), t = 0 .. infinity);
                              1  
                              - s
                              2  
 

 

different answers to same command...

rrbaldino 55 Maple 2016
2dmath sum
September 13 2017
1 0

Why do I get different answers for the same command?

 different_answers.mw


 

``

> 

restart
> 

x := proc (n) options operator, arrow; cos(n*Pi) end proc;

proc (n) options operator, arrow; cos(n*Pi) end proc

 (1)
> 

"f:=k->"sum(k*x(n), n = 2 .. 3);f(1);

0

  

f(1)

 (2)
> 

f := proc (k) options operator, arrow; sum(k*x(n), n = 2 .. 3) end proc;

proc (k) options operator, arrow; sum(k*x(n), n = 2 .. 3) end proc

  

0

 (3)
> 

``


 

Download different_answers.mw

Why do I get different solutions for har...

rrbaldino 55 Maple
differential-equation dsolve dirac
June 11 2017
2 5


 

> 

restart
> 

eq := diff(y(t), t, t)+9*y(t) = Dirac(t)

diff(diff(y(t), t), t)+9*y(t) = Dirac(t)

 (1)
> 

with(inttrans):
> 

icon := y(0) = 0, (D(y))(0) = 0;

y(0) = 0, (D(y))(0) = 0

 (2)
> 

dsolve({eq, icon}, y(t), method = laplace);

y(t) = (1/3)*sin(3*t)

 (3)
> 

dsolve({eq, icon}, y(t));

y(t) = (1/3)*(Heaviside(t)-1/2)*sin(3*t)

 (4)

``


 

Download Dirac_for_Primes.mw

Plot DE solution with unapply...

rrbaldino 55 Maple
March 04 2017
1 1

I want to use the solutuion of a DE as a function, including the possibility to plot it.

I have found out that the following comands work, but I cannot undesrtand why. Is there a simpler way?

Truly, Roberto R. Baldino

sol := dsolve({eq, icon}, i(t));
i := unapply(eval(i(t), sol), t);
plot(i(t), t = 0 .. 20, view = [-1 .. 20, -3 .. 3], gridlines);

hatching number in 3d plots...

rrbaldino 55
hatching
December 22 2016
2 1

How to change the numer of hatchings in a 3d plot?

 

1 2 3 Page 1 of 3