mehdi jafari

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convert convolution integral to series...

Asked: mehdi jafari 749

November 22 2014

0 0

hi everyone , i need your point of view in my question,any help would be appreciated in advance .

we have a discrete function named g(t) and a continous function f(t) in in convolution integral just like this :
int(f(t-x)*g(x),x=0..t) ;
we have just g(x) in some special points int the interval (0..t) , thus i need to convert this integral to a series.
how should i do this ? can anyone help or any idea ? i need at first a mathematical solution or idea about how to do this and then, how to do this in a software ?
tnx again.

problem with for loop...

Asked: mehdi jafari 749

August 06 2014

2 0

i want to define a loop for like this :

for i from 0 to 100 by 0.2 do; ... ; od ;

i want when this loop finishes,the the loop turns to exactly vice versa respect,and continue , i mean it continue like this :
for i from 100 to 0 by -0.2 ... ,

can anybody help me to find an algorithm for this ? tnx in advance

why this integral does not return anythi...

Asked: mehdi jafari 749

July 29 2014

0 5

restart:

>	l := 16; m := .75; EIy := 0.2e5; EIz := 0.400e7; GJ := 0.1e5; mj := .1; Pz := 5000;

(1)

>	eq1 := m(diff(diff(w(x, t), t), t))+diff(diff(EIy(diff(diff(w(x, t), x), x))+(EIz-EIy)(diff(diff(w(x, t), x), x))(theta(x)+phi(x, t))^2, x), x)-Pz = 0;

(2)

>	w := unapply(q[1](t)cosh(1.8751x/l),x, t);

(3)

>	theta := proc (x) options operator, arrow; 0 end proc;

(4)

>	#theta(x);eq1;

>	phi := unapply(q[4](t)sin(1.5708x/l),x, t);

(5)

>	eq2:=unapply(lhs(eq1),x,t);

proc (x, t) options operator, arrow; .75*(diff(diff(q[1](t), t), t))*cosh(.1171937500*x)+3.772661154*q[1](t)*cosh(.1171937500*x)-302.9569534*q[1](t)*cosh(.1171937500*x)*q[4](t)^2*sin(0.9817500000e-1*x)^2+2515.691179*q[1](t)*sinh(.1171937500*x)*q[4](t)^2*sin(0.9817500000e-1*x)*cos(0.9817500000e-1*x)+1053.716523*q[1](t)*cosh(.1171937500*x)*q[4](t)^2*cos(0.9817500000e-1*x)^2-5000 end proc

(6)

>	f[1] := int(expand(eq2(x,t)cosh(1.8751x/l)), x = 0 .. l);

(7)

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problem with integrations, bug in maple ...

Asked: mehdi jafari 749

July 13 2014

6 0

can i compute this integral so that the answer does not have any complex part ? i just want the integral returns me real function or number .
i also use evalf(int ... ) and evalf(Int ... ) and two different answers were given ! what is wrong ?
tnx for help in advance .

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convert data readed from text file to ar...

Asked: mehdi jafari 749

July 12 2014

1 3

i have read data from a text file. i want to convert this data to array,how should i do that ?

for example :
i have readed these files and i want convert them to array which for the first one,has 3 rows and 4 columns.
what should i do ?