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How to solve the equation
2^(sin(x)^4-cos(x)^2)-2^(cos(x)^4-sin(x)^2) = cos(2*x)
symbolically? The solve command produces a weird answer. Evalfing all its values, one sees
0.7853981634, -0.7853981634, 2.356194490, -2.356194490,

1.570796327 - 1.031718534 I, -1.570796327 + 1.031718534 I,

1.570796327 + 1.031718534 I, -1.570796327 - 1.031718534 I,

0.7853981634, -0.7853981634, 2.356194490, -2.356194490,

1.570796327 - 1.031718534 I, -1.570796327 + 1.031718534 I,

1.570796327 + 1.031718534 I, -1.570796327 - 1.031718534 I


The identify command
interprets the real solutions on -Pi..Pi as -3*Pi/4, -Pi/4, Pi/4, 3*Pi/4
(for example,
identify(2.356194490);

3*Pi/4 ).
Is it possible to obtain these with Maple in a simpler way?

PS. Mathematica 10 does the job.

PPS. So does even Mathematica 7.

Hi i 2 questions. all pertaining to solving a systems of equations mod 2

First if i have a large set of equations, 11^3 equations in 11 unknowns and i want maple to give me ALL solutions mod 2 how can i do that? Maples msolve is loosing solutions.

Second suppose i want all unique solutions that say 6 of the variables can have but dont care what the solution to the other variables are as long as it is a solution. 

mini example:

say x=1,y=1,z=1 is a solution as well as x=1,y=1,z=0, i just want to know about x=1,y=1.

 

How to solve the system
{sqrt((x-1)^2+(y-5)^2)+(1/2)*abs(x+y) = 3*sqrt(2), sqrt(abs(x+2)) = 2-y}
over the reals symbolically? Of course, with Maple. Mathematica does the job.

Hi,

I'm trying to solve the following non-linear ODE numerically:

by ececuting

but maple gives me this error-message:

"Error, (in dsolve/numeric/make_proc) Could not convert to an explicit first order system due to 'RootOf'"

I couldnt find any useful information in the manual. What does this error mean? Is there something wrong with my maple code or is there just no solution for this particulare differential equation?

 

Thanks in advance

Hi

I have this PDE and was wondering how I can get Maple to solve it

utt+2ut-uxx=18sin(3πx/l)

with conditions u(0,t)=u(l,t)=0 and u(x,0)=ut(x,0)=0

Thanks

James

 

 

 

Hi,

 

I'm trying to solve the following differential equation numerically with dsolve:

but dsolve gives me this error:

> res := dsolve(DGL, numeric, parameters = [y0, A, B, C, E]);
Error, (in DEtools/convertsys) unable to convert to an explicit first-order system

I think the problem is that I use the wrong solver. Does Maple provide a solver which is capable of solving this kind of equations (nonlinear ODE)?

 

Thanks in advance!

 

Hello guys

I have a linear differentional equation which is in the 4th order. It is shown in the below:

P:=phi(x):
eq:=a11*diff(p,x,x,x,x)+a22*diff(p,x,x)+a33*p:
eq:=0:
where a11 and a22 and a33 are constant coefficients. The boundary value for this equation is:

phi(a)=sigma1 , phi(-a)=sigma1 , diff(p,x)(a)=0 , diff(p,x)=0

Now consider :

a11:=2.731e-10:
a22:=-1.651e-9:
a33:=3.09027e-10:
a:=35.714:
sigma1:=200e6:

when I use dsolve for deriving a good answer in this equation. there are four real roots .How can I solve it with these boundary condition?

I need to extract phi(x) from this equation.

Thanks

Dear friends,

Recently I was surprised when discovered the following error in using the function solve. If I run the simlest example from the help system for the first time (or after restarting), the following error occurs:

If I run this example repeatedly, this brings the following:

1

Previously in earlier versions I used solve many times for very complex computations and have never seen something similar.

Any suggestions are welcomed.

Naive simplification of f(z)=sqrt(z-1)*sqrt(-1*(-z-1)) to F(z)=sqrt(z^2-1)results in a pair of functions that agree on only part of the complex plane. In this application, the enhanced ability of Maple 18 to find and display branch cuts of composite functions is used to explore the branch cuts and regions of agreement/disagreement of f and F.

The algorithm by which Maple calculates branch cuts for square-root functions involves squaring, to remove the square root, and solving appropriate equations and inequalities. Unfortunately, this process is inherently prone to introducing spurious solutions, in which case the returned branch cut is not correct. One such instance in which a spurious solution arises is in the calculation of the branch cut for f; a best suggestion for dealing with such errors is found in the application.

Application: Branch Cuts for a Product of Two Square Roots

For those interested in learning more, the design for the new branch-cut facility in Maple 18 is inspired by the following paper:

England, M., Bradford, R., Davenport, J. H., and Wilson, D. 2013.  Understanding branch cuts of expressions. In: Carette, J., Aspinall, D., Lange, C., Sojka, P. and Windsteiger, W., eds.  Intelligent Computer Mathematics. Berlin: Springer, pp. 136-151. (Lecture Notes in Computer Science; 7961)

Today I have a problem with assign that never arised before. I solved a system of equations with two solutions and wanted to assign, e.g. the second one. Does anybody know why "assign" here does not work, even though I often used it before in the same way. (I also tried it with the array-solution, but I received the same problem.

Output:

 

  {rH = 0., rL = 0., xH = 0.2289428485, xL = 0.2289428485}, {

    rH = 22.70954353, rL = 32.28670872, xH = 0.4250775404,

    xL = 0.4393791233}
  {rH = 0., rL = 0., xH = 0.2289428485, xL = 0.2289428485}, {

    rH = 22.70954353, rL = 32.28670872, xH = 0.4250775404,

    xL = 0.4393791233}
assign {rH = 22.70954353, rL = 32.28670872, xH = 0.4250775404,

  xL = 0.4393791233}
                         rL, rH, xL, xH


I would be very glad, if anybody could help me.

And here is the whole algorithm:

 

 

 

 

How would one in Maple solve this, which is an inequality equation in some variables, which can be nonlinear, with constraints on range of each variable. I.e. I want to find conditions on the variables to make the inequality satisfied.

In Mathematica, I use the Reduce command

Clear[x, y];
eq = 1/2 - x + x^2 - y + y^2;
Reduce[{eq > 0, 0 < x < 1 && 0 < y < 1}, {x, y}, Reals]

How would one do the same in Maple? I tried solve, but can't give constraints.

restart;
eq:=1/2 -x+x^2-y+y^2:
solve(eq>0 , {x1, x2});

So I need to do the same as in the Mathematica command, but in Maple. I do not want numerical solution, but algebraic as shown above.

Using Maple 18.2 on windows.

following commands on my computer got an error.

restart;
with(LinearAlgebra):
A:=Matrix([[1,3],[2,5]],datatype=float):
b:=Vector([1,1],datatype=float):
LinearSolve(A,b,method=hybrid);
Error, (in SWcallhybrid[1]) param 4 should be an rtable

any suggestion is appreciated.

win7, 12.02

I have a characteristic equation. some times It has polar roots . sometimes It has real roots and sometimes both of them.

I want to extract real roots and extract polar roots if they are.

for instance:

q:=m3*r^3+m2*r^2+m1*r+m0:

rot:=solve(q=0,r);

I want to know how can I use if in this part ?

hi

i have solved my equation as folllow :

 

pde:= diff(T(x, y), x)-1.555*10^(-7)*(diff(T(x, y), y, y))/ ...........

 

sol := pdsolve(pde, {T(0, y) = 0, (D[2](T))(x, 0) = 1325.754092, (D[2](T))(x, 0.25e-4) = 1970434.783}, numeric)

 

I wana know that maple has used which of numeric method to solve my equation ?

 

1.ForwardTime1Space[forward/backward]

2.CenteredTime1Space[forward/backward]

3.BackwardTime1Space[forward/backward]

4.ForwardTimeCenteredSpace or Euler

5.CenteredTimeCenteredSpace or CrankNicholson

6.BackwardTimeCenteredSpace or BackwardEuler

7.Box

8.LaxFriedrichs

or ... ?

 

Tahnks.

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