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mehdi jafari

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i think u misunderstand the problem,...

mehdi jafari 774
September 03 2013
0 0

thank u for your attention and help,

i think u misunderstand the problem, since my problem is that K2.V is not equal to W's.
and also i need to set free the remaining b's. i think there is a problem with number of digits after decimal point so that such a problem occur. see my code below :

> 

(K(t).V(t))(6,1)-SS2(t)(6,1);

.1*a[29](t)^2-.2*a[28](t)^2-.2*a[26](t)*a[30](t)-.1*a[26](t)*a[29](t)+.1*a[27](t)*a[28](t)+.1*a[26](t)*a[28](t)-0.1e-1*a[25](t)*a[26](t)-0.1e-3*a[17](t)-0.2e-3*a[9](t)-0.1e-1*a[2](t)

 (1)
> 

(K(t).V(t))(6,1);

-1320775813.*a[30](t)^2-950399527.*a[29](t)^2-614104310.*a[28](t)^2-326591837.5*a[27](t)^2-110879944.8*a[26](t)^2-2245318883.*a[29](t)*a[30](t)-1824767092.*a[28](t)*a[30](t)-1381734697.*a[27](t)*a[30](t)-1535260775.*a[28](t)*a[29](t)-921156465.*a[26](t)*a[30](t)-1151445581.*a[27](t)*a[29](t)-453599774.3*a[25](t)*a[30](t)-755999624.*a[26](t)*a[29](t)-907199548.5*a[27](t)*a[28](t)-362879819.5*a[25](t)*a[29](t)-580607711.*a[26](t)*a[28](t)-266111867.6*a[25](t)*a[28](t)-399167801.4*a[26](t)*a[27](t)-166319917.2*a[25](t)*a[27](t)-71279964.55*a[25](t)*a[26](t)+377999.8119*a[24](t)+302399.8495*a[23](t)+221759.8897*a[22](t)+138599.9310*a[21](t)+59399.97045*a[20](t)+1133999.436*a[18](t)+907199.5485*a[17](t)+665279.6690*a[16](t)+415799.7931*a[15](t)+178199.9113*a[14](t)+1889999.060*a[12](t)+1511999.248*a[11](t)+1108799.448*a[10](t)+692999.6550*a[9](t)+296999.8522*a[8](t)-453599774.3*a[6](t)-362879819.5*a[5](t)-266111867.6*a[4](t)-166319917.2*a[3](t)-71279964.55*a[2](t)

 (2)
> 

SS2(t)(6,1);

-1320775813.*a[30](t)^2-950399527.1*a[29](t)^2-614104309.8*a[28](t)^2-326591837.5*a[27](t)^2-110879944.8*a[26](t)^2-2245318883.*a[29](t)*a[30](t)-1824767092.*a[28](t)*a[30](t)-1381734697.*a[27](t)*a[30](t)-1535260775.*a[28](t)*a[29](t)-921156464.8*a[26](t)*a[30](t)-1151445581.*a[27](t)*a[29](t)-453599774.3*a[25](t)*a[30](t)-755999623.9*a[26](t)*a[29](t)-907199548.6*a[27](t)*a[28](t)-362879819.5*a[25](t)*a[29](t)-580607711.1*a[26](t)*a[28](t)-266111867.6*a[25](t)*a[28](t)-399167801.4*a[26](t)*a[27](t)-166319917.2*a[25](t)*a[27](t)-71279964.54*a[25](t)*a[26](t)+377999.8119*a[24](t)+302399.8495*a[23](t)+221759.8897*a[22](t)+138599.9310*a[21](t)+59399.97045*a[20](t)+1133999.436*a[18](t)+907199.5486*a[17](t)+665279.6690*a[16](t)+415799.7931*a[15](t)+178199.9113*a[14](t)+1889999.060*a[12](t)+1511999.248*a[11](t)+1108799.448*a[10](t)+692999.6552*a[9](t)+296999.8522*a[8](t)-453599774.3*a[6](t)-362879819.5*a[5](t)-266111867.6*a[4](t)-166319917.2*a[3](t)-71279964.54*a[2](t)

 (3)
> 

 

as u can see,since there are two many digits after decimal point,thus this problems happen.
could u please help me ?

Download problem_2.mws

i think u misunderstand the problem,...

mehdi jafari 774
September 03 2013

thank u for your attention and help,

i think u misunderstand the problem, since my problem is that K2.V is not equal to W's.
and also i need to set free the remaining b's. i think there is a problem with number of digits after decimal point so that such a problem occur. see my code below :

> 

(K(t).V(t))(6,1)-SS2(t)(6,1);

.1*a[29](t)^2-.2*a[28](t)^2-.2*a[26](t)*a[30](t)-.1*a[26](t)*a[29](t)+.1*a[27](t)*a[28](t)+.1*a[26](t)*a[28](t)-0.1e-1*a[25](t)*a[26](t)-0.1e-3*a[17](t)-0.2e-3*a[9](t)-0.1e-1*a[2](t)

 (1)
> 

(K(t).V(t))(6,1);

-1320775813.*a[30](t)^2-950399527.*a[29](t)^2-614104310.*a[28](t)^2-326591837.5*a[27](t)^2-110879944.8*a[26](t)^2-2245318883.*a[29](t)*a[30](t)-1824767092.*a[28](t)*a[30](t)-1381734697.*a[27](t)*a[30](t)-1535260775.*a[28](t)*a[29](t)-921156465.*a[26](t)*a[30](t)-1151445581.*a[27](t)*a[29](t)-453599774.3*a[25](t)*a[30](t)-755999624.*a[26](t)*a[29](t)-907199548.5*a[27](t)*a[28](t)-362879819.5*a[25](t)*a[29](t)-580607711.*a[26](t)*a[28](t)-266111867.6*a[25](t)*a[28](t)-399167801.4*a[26](t)*a[27](t)-166319917.2*a[25](t)*a[27](t)-71279964.55*a[25](t)*a[26](t)+377999.8119*a[24](t)+302399.8495*a[23](t)+221759.8897*a[22](t)+138599.9310*a[21](t)+59399.97045*a[20](t)+1133999.436*a[18](t)+907199.5485*a[17](t)+665279.6690*a[16](t)+415799.7931*a[15](t)+178199.9113*a[14](t)+1889999.060*a[12](t)+1511999.248*a[11](t)+1108799.448*a[10](t)+692999.6550*a[9](t)+296999.8522*a[8](t)-453599774.3*a[6](t)-362879819.5*a[5](t)-266111867.6*a[4](t)-166319917.2*a[3](t)-71279964.55*a[2](t)

 (2)
> 

SS2(t)(6,1);

-1320775813.*a[30](t)^2-950399527.1*a[29](t)^2-614104309.8*a[28](t)^2-326591837.5*a[27](t)^2-110879944.8*a[26](t)^2-2245318883.*a[29](t)*a[30](t)-1824767092.*a[28](t)*a[30](t)-1381734697.*a[27](t)*a[30](t)-1535260775.*a[28](t)*a[29](t)-921156464.8*a[26](t)*a[30](t)-1151445581.*a[27](t)*a[29](t)-453599774.3*a[25](t)*a[30](t)-755999623.9*a[26](t)*a[29](t)-907199548.6*a[27](t)*a[28](t)-362879819.5*a[25](t)*a[29](t)-580607711.1*a[26](t)*a[28](t)-266111867.6*a[25](t)*a[28](t)-399167801.4*a[26](t)*a[27](t)-166319917.2*a[25](t)*a[27](t)-71279964.54*a[25](t)*a[26](t)+377999.8119*a[24](t)+302399.8495*a[23](t)+221759.8897*a[22](t)+138599.9310*a[21](t)+59399.97045*a[20](t)+1133999.436*a[18](t)+907199.5486*a[17](t)+665279.6690*a[16](t)+415799.7931*a[15](t)+178199.9113*a[14](t)+1889999.060*a[12](t)+1511999.248*a[11](t)+1108799.448*a[10](t)+692999.6552*a[9](t)+296999.8522*a[8](t)-453599774.3*a[6](t)-362879819.5*a[5](t)-266111867.6*a[4](t)-166319917.2*a[3](t)-71279964.54*a[2](t)

 (3)
> 

 

as u can see,since there are two many digits after decimal point,thus this problems happen.
could u please help me ?

Download problem_2.mws

thnx...

mehdi jafari 774
September 02 2013
0 0

actually it is not important for me to be inversible,i just want K2.Vt gives me original equations,
how about first question? can i collect them as i want it?
i am really thankful for your attention and help.

thnx...

mehdi jafari 774
September 02 2013

actually it is not important for me to be inversible,i just want K2.Vt gives me original equations,
how about first question? can i collect them as i want it?
i am really thankful for your attention and help.

yesss...

mehdi jafari 774
September 02 2013

@Carl Love  i want it to collect the expressions that only has a[3]. not the other ones.

for example i want it give me a[1]*a[2]*a[3]+a[3]^3.

i do not want to use for example this command

select(has,eq1,a[3]). i need to use collect beacuse my main problem is another one.

i have 3 equations.

eq1:=a[1](t)*a[2](t)^2+a[2](t)*a[3](t)*a[1]+a[3](t)^3;
eq2:=a[1](t)^3*a[2](t)^2+a[2](t)*a[3](t)+a[2](t)^3;
eq3:=a[1](t)*a[3](t)^2+a[3](t)^2*a[1](t)^3+a[2](t);

i want to write them like this 

<eq1,eq2eq3>;=[3*3 matrix including coefficients]*<a[1],a[2],a[3]>.

i need coefficients matrix.

last time Preben Alsholm helped me,with using equate command,but when range of equations go higher,multiplying the coefficients matrix in coefficients itself does not give me back the original equations.

http://www.mapleprimes.com/questions/149035-Convert-To-Vector-Mode

i need to use another way to produce this matrix,do anyone has any comment that how can i do that?

in fact in the page that i have reffered to,K1.V does not give the original equations for me,not in this 3*3 matrix,
i face problem in 18*18 or higher order matrix, 
here is the code, and 9 of these equations are not correct.problem_2.mws 

put your system of ode's here,...

mehdi jafari 774
September 02 2013

i think u should put your system here so that everybody can evaluate the situation better.


thnx...

mehdi jafari 774
September 01 2013
0 0

@Markiyan Hirnyk i actully do this after that,it made the problem solved. thnx.

thnx...

mehdi jafari 774
September 01 2013

@Markiyan Hirnyk i actully do this after that,it made the problem solved. thnx.

thnx...

mehdi jafari 774
September 01 2013
0 0

@Markiyan Hirnyk thank u,really.
i have another question, how can i use these values for further equations ?
i mean after solving these equations, when i type a[1](0.0001) it simply returns just itself,not the result that fsolve find,what should i do here? actually i want to assign the values that fsolve has found to the unkowns,what should i do ?

thnx...

mehdi jafari 774
September 01 2013

@Markiyan Hirnyk thank u,really.
i have another question, how can i use these values for further equations ?
i mean after solving these equations, when i type a[1](0.0001) it simply returns just itself,not the result that fsolve find,what should i do here? actually i want to assign the values that fsolve has found to the unkowns,what should i do ?

what do u want exactly to do here?...

mehdi jafari 774
September 01 2013
0 0

@Mathematix u want the answer to the third question ?! but the problem are not the same.since u have written exp(-3) but it is exp(-3*x) . your answer seems to be somewhat simpler but for more skillful member i think.
but both are doing the same thing.

if you write it in this way,(exp(-3*x)) u can easily do this just like u said,without needing using subs command :

 

de := diff(y(x), `$`(x, 2))+4*y(x) = exp(-3*x);

  

``


Download answer.mw

what do u want exactly to do here?...

mehdi jafari 774
September 01 2013

@Mathematix u want the answer to the third question ?! but the problem are not the same.since u have written exp(-3) but it is exp(-3*x) . your answer seems to be somewhat simpler but for more skillful member i think.
but both are doing the same thing.

if you write it in this way,(exp(-3*x)) u can easily do this just like u said,without needing using subs command :

> 

de := diff(y(x), x$2)+4*y(x) = exp(-3*x);

Y := rhs(dsolve({de, y(0) = 2, (D(y))(0) = 0}, y(x)));

plot(Y, x = -1 .. 1);

de := diff(y(x), `$`(x, 2))+4*y(x) = exp(-3*x)

Y := (3/26)*sin(2*x)+(25/13)*cos(2*x)+(1/13)*exp(-3*x)

  
> 

 

 

Download answer.mws

variable are function of time...

mehdi jafari 774
September 01 2013
0 0

these variables are function of times , when i use a[1](0.0001) it means a[1] for the time t=0.0001:

i need to have them as a function of time , so i can not remove (i+h=0.0001).i even use subs to substitute a[i](t)=b[i] but it does not solve the problem, i really do not know what should i do ?!

and as far as i know, {seq(expr,k=1..18)} = {seq}(expr,k=1..18) . am i wrong?

variable are function of time...

mehdi jafari 774
September 01 2013

these variables are function of times , when i use a[1](0.0001) it means a[1] for the time t=0.0001:

i need to have them as a function of time , so i can not remove (i+h=0.0001).i even use subs to substitute a[i](t)=b[i] but it does not solve the problem, i really do not know what should i do ?!

and as far as i know, {seq(expr,k=1..18)} = {seq}(expr,k=1..18) . am i wrong?

woww...

mehdi jafari 774
August 29 2013

@Carl Love perfect,really nice.

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