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Hi everyone,

 

I have a question regarding the simplification of an equation. Suppose I have and equation in maple such as (4*y^2 + 8*y + 8*sin(y))/(y^2 +1)=0. Is there a sequence of commands in Maple to simpliy this equation to (1/2)y^2 + y + sin(y)=0?

 

I know mulitplying the entire original equation by (1/8)*(y^2+1) would achieve the objective, but the equations I am generating are much longer and more complicated. The example above was chosen just to illustrate the goal.

 

Best,

 

Justin

Hello Maple-Primers!

I am trying to evaluate a system at many different points.  I would like to include an interpolation function in this system, but have thusfar been unsuccessful.

Usually, I solve a system symbolically by using eliminate and unapply:

eq[1] := A = M^3;
eq[2] := C = A*2;
eq[3] := D = N+3;
eq[4] := B = piecewise(A = 0, 0,C);
eq[5] := E = B*D;
elimsol:=eliminate(convert(eq,list),[A,B,C,D,E])[1];

unappsol:=unapply(elimsol,[N,M]);

unappsol(1,2);
{A = 8, B = 16, C = 16, D = 4, E = 64} <--- great!

Now, I want to include an interpolation function in the system of equations.  They look like this (see worksheet for actual interpolation function):

B_interp := (W,T) -> CurveFitting:-ArrayInterpolation([FC_Map_W,FC_Map_T],FC_Map,Array(1 .. 1, 1 .. 1, 1 .. 2, [[[W, T]]]),method=linear);

eq[5] := E = B_interp(N,M);

Error, (in CurveFitting:-ArrayInterpolation) invalid input: coordinates of xvalues must be of type numeric <-- bad!

Anyone have any ideas?  I've tried to use polynomials, but I can't seem to get a fit close enough for my purposes.

Maple_2D_Interpolate_FC.mw

Hello,

       How long can I expect Maple17 to take to algebraically solve a system of 14 nonlinear equations that has approximately 40% nonlinearity in its terms? I am running it on the machine right now, but have no idea what to expect. As mentioned before, I'm new to Maple...

Here is my code:

restart; eq1 := A*z-B*a*z-V*a*q-W*(b+d)*a = 0; eq2 := W*(b+d)*a-V*b*q-(F*G+B+D)*b*z = 0; eq3 := V*a*q-W*c*(b+d)-(B+C+E)*c*z = 0; eq4 := V*b*q+W*(b+d)*c-(B+C+D+F)*d*z = 0; eq5 := G*F*b*z-V*q*e-(B+H)*e*z = 0; eq6 := H*e*z-V*q*f-(B+S)*f*z = 0; eq7 := S*f*z-V*q*g-B*g*z = 0; eq8 := V*q*g+S*s*z-(B+C+E)*h*z = 0; eq9 := F*d*z+V*q*e-(B+C+H+T)*t*z = 0; eq10 := H*t*z+V*q*f-(U+B+C+2*S)*s*z = 0; eq11 := T*t*z-(B+H+Y)*u*z = 0; eq12 := U*s*z-(B+S)*v*z+H*u*z-Y*H*v*z/(H+S) = 0; eq13 := g-c-d-t-s-h = 0; eq14 := z-a-b-c-d-e-f-g-h-s-t-u-v = 0; soln := solve({eq1, eq10, eq11, eq12, eq13, eq14, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, {a, b, c, d, e, f, g, h, q, s, t, u, v, z});

Thanks.

 

 

Hello,

       I am new to this forum. I have typed the follwing code in Maple17:

restart; eq1 := A-B*a-V*a*q/z-W*(b+d)*a/z = 0; eq2 := W*(b+d)*a/z-V*b*q/z-(F*G+B+D)*b = 0; eq3 := V*a*q/z-W*c(b+d)/z-(B+C+E)*c = 0; eq4 := V*b*q/z+W*(b+d)*c/z-(B+C+D+F)*d = 0; eq5 := G*F*b-V*q*e/z-(B+H)*e = 0; eq6 := H*e-V*q*f/z-(B+S)*f = 0; eq7 := S*f-V*q*g/z-B*g = 0; eq8 := V*q*g/z+S*s-(B+C+E)*h = 0; eq9 := F*d+V*q*e/z-(B+C+H+T)*t = 0; eq10 := H*t+V*q*f/z-(U+B+C+2*S)*s = 0; eq11 := T*t+W*(b+d)*x/z-(B+H+Y)*u = 0; eq12 := U*s-(B+S)*v+H*u-Y*H*v/(H+S) = 0; eq13 := g-c-d-t-s-h = 0; eq14 := z-a-b-c-d-e-f-g-h-s-t-u-v = 0; soln := solve({eq1, eq10, eq11, eq12, eq13, eq14, eq2, eq3, eq4, eq5, eq6, eq7, eq8, eq9}, {a, b, c, d, e, f, g, h, q, s, t, u, v, z});

 

This is to symbolically solve a nonlinear system of (14) equations. But when I press Enter, it just returns the message "Ready". Shouldn't it say "Evaluating"?

I don't see anything syntactically wrong with my code...

http://vk.com/doc242471809_295040421

The new method and approach to the calculation of the geometry and kinematics linkages. It is based on the Draghilev method for solving systems of nonlinear equations.

( 10-bar linkage spherical mechanism animation. Program text for professionals only.)

MECHAN123_SPHERE_10.mw

 

I'm having some trouble maybe someone can point out my error please. I'm using the Maple 18 worksheet to try some basic linear equations. The trouble is in the last step.

 

1.) I start with 2 ordered pairs (2, 14) and (14,18)

Then I put in my formula to discover the slope. I confirm it looks correct in the Variables window.

m := (y2-y1)/(x2-x1);

 

2.)  Next I input the values for my ordered pairs. I also confirm thru the Variables window.

x1 := 2;

y1 := 14;

x2 := 3;

y2 := 18;

 

3.) Now I can type m and expect to get an answer to what my slope is.

m;

4.) Now I want Slope/Intercept form of y=mx+b. When I put in the formula y-y1=m(x-x1) i get a strange result

 

When I execute this formula, the result is y-14=4. (or thru context menu I tell it to solve for y, then I get y=18)

y-y1=m(x-x1) 

When I manually input the values, the output is y-14=4x-8 (or thru context menu I tell it to solve for y, then I get y=4x+6)

y-14 = 4*(x-2)

 

 

 

Why is my equation (y-y1=m(x-x1)) not executing properly?

How can I solve raychaudhuri equations numerically using GRtensor?

Hi,

how can I solve a set of first order, coupled, non-linear and inhomogeneous differential equations using MAPLE 12.

Hi every body:

how can i solve this equations(without numerical method):

eq1 := (D[1, 1](eta11))(t, a*t, a^2*t)+1.326096634*10^8*Pi^2*eta11(t, a*t, a^2*t)-3.315241586*10^7*Pi*eta21(t, a*t, a^2*t) = 0

eq2 := 2.054901810*10^13*eta21(t, a*t, a^2*t)+(D[1, 1](eta21))(t, a*t, a^2*t)-8.219607239*10^13*Pi*eta11(t, a*t, a^2*t)+4.137421500*10^8*Pi^2*eta21(t, a*t, a^2*t) = 0

eq3 := (D[1, 1](eta31))(t, a*t, a^2*t)+4.137421500*10^8*Pi^2*eta31(t, a*t, a^2*t) = 0

Hi,

I have this set of equations but maple won't solve the three variables and it gives an 

Error, (in solve) cannot solve for an unknown function with other operations in its arguments. This are the equations with unknowns, alfa1, alfa2, and alfa3.

eq1 := 3*(1+sin(alfa1)^3)(30/tan(alfa1)+60/tan(alfa2)+60/tan(alfa3))/(sin(alfa1)^2*cos(alfa1)*tan(alfa1)) = 3*(1+sin(alfa2)^3)(30/tan(alfa2)+60/tan(alfa3))/(sin(alfa2)^2*cos(alfa2)*tan(alfa2));

eq2 := 3*(1+sin(alfa1)^3)(30/tan(alfa1)+60/tan(alfa2)+60/tan(alfa3))/(sin(alfa1)^2*cos(alfa1)*tan(alfa1)) = (90*(1+sin(alfa3)^3))/(sin(alfa3)^2*cos(alfa3)*tan(alfa3));

eq3 := 3/tan(alfa1)+3/tan(alfa2)+3/tan(alfa3) = 25/2;

solutions := [solve({eq1, eq2, eq3, alfa1 > 0, alfa2 > 0, alfa3 > 0}, {alfa1, alfa2, alfa3})];

Can anyone help?

 

im solving 6 ODE which is the equations are unsteady with boundary conditions.. the program can be run when A=0 but when A=0.2 or others value .. its cannot be run... A means for unsteadiness... before this i solve for steady equations.. this is first time i solve for unsteady using maple.. anyone know where i am wrong??? thanks for helping :)

 

restart; with(plots); n := 2; Ec := 2.0; Pr := .72; N := .2; M := .1; l := 1; Nr := 1; y := 1; blt := 2.5; B := .1; a1 := 1; rho := .5

Eq1 := diff(f(eta), eta, eta, eta)+f(eta)*(diff(f(eta), eta, eta))-(diff(f(eta), eta))^2+l*B*H(eta)*(F(eta)-(diff(f(eta), eta)))-M*(diff(f(eta), eta))-A*(diff(f(eta), eta)+.5*eta*(diff(f(eta), eta, eta))) = 0;

diff(diff(diff(f(eta), eta), eta), eta)+f(eta)*(diff(diff(f(eta), eta), eta))-(diff(f(eta), eta))^2+.1*H(eta)*(F(eta)-(diff(f(eta), eta)))-.1*(diff(f(eta), eta))-A*(diff(f(eta), eta)+.5*eta*(diff(diff(f(eta), eta), eta))) = 0

(1)

Eq2 := A*(F(eta)+.5*eta*(diff(F(eta), eta)))+G(eta)*(diff(F(eta), eta))+F(eta)^2+B*(F(eta)-(diff(f(eta), eta))) = 0;

A*(F(eta)+.5*eta*(diff(F(eta), eta)))+G(eta)*(diff(F(eta), eta))+F(eta)^2+.1*F(eta)-.1*(diff(f(eta), eta)) = 0

(2)

Eq3 := .5*A*(G(eta)+.5*eta*(diff(G(eta), eta)))+G(eta)*(diff(G(eta), eta))+B*(f(eta)+G(eta)) = 0;

.5*A*(G(eta)+.5*eta*(diff(G(eta), eta)))+G(eta)*(diff(G(eta), eta))+.1*f(eta)+.1*G(eta) = 0

(3)

Eq4 := G(eta)*(diff(H(eta), eta))+H(eta)*(diff(G(eta), eta))+F(eta)*H(eta) = 0;

G(eta)*(diff(H(eta), eta))+H(eta)*(diff(G(eta), eta))+F(eta)*H(eta) = 0

(4)

Eq5 := (1+Nr)*(diff(theta(eta), eta, eta))+Pr*((diff(theta(eta), eta))*f(eta)-2*(diff(f(eta), eta))*theta(eta))+N*Pr*a1*(theta1(eta)-theta(eta))/rho+N*Pr*Ec*B*(F(eta)-(diff(f(eta), eta)))^2/rho+Pr*Ec*(diff(f(eta), eta))^2-.5*A*Pr*(4*theta(eta)+eta*(diff(theta(eta), eta))) = 0;

2*(diff(diff(theta(eta), eta), eta))+.72*(diff(theta(eta), eta))*f(eta)-1.44*(diff(f(eta), eta))*theta(eta)+.2880000000*theta1(eta)-.2880000000*theta(eta)+0.5760000000e-1*(F(eta)-(diff(f(eta), eta)))^2+1.440*(diff(f(eta), eta))^2-.360*A*(4*theta(eta)+eta*(diff(theta(eta), eta))) = 0

(5)

Eq6 := 2*F(eta)*theta1(eta)+G(eta)*(diff(theta1(eta), eta))+a1*y*(theta1(eta)-theta(eta))+.5*A*(4*theta1(eta)+eta*(diff(theta1(eta), eta))) = 0;

2*F(eta)*theta1(eta)+G(eta)*(diff(theta1(eta), eta))+theta1(eta)-theta(eta)+.5*A*(4*theta1(eta)+eta*(diff(theta1(eta), eta))) = 0

(6)

bcs1 := f(0) = 0, (D(f))(0) = 1, (D(f))(blt) = 0, F(blt) = 0, G(blt) = -f(blt), H(blt) = n, theta(0) = 1, theta(blt) = 0, theta1(blt) = 0;

f(0) = 0, (D(f))(0) = 1, (D(f))(2.5) = 0, F(2.5) = 0, G(2.5) = -f(2.5), H(2.5) = 2, theta(0) = 1, theta(2.5) = 0, theta1(2.5) = 0

(7)

L := [0., .2, .5];

[0., .2, .5]

(8)

for k to 3 do R := dsolve(eval({Eq1, Eq2, Eq3, Eq4, Eq5, Eq6, bcs1}, A = L[k]), [f(eta), F(eta), G(eta), H(eta), theta(eta), theta1(eta)], numeric, output = listprocedure); Y || k := rhs(R[3]); YP || k := rhs(R[5]); YR || k := rhs(R[6]); YQ || k := rhs(R[7]); YA || k := rhs(R[9]); YB || k := rhs(R[8]) end do

Error, (in dsolve/numeric/bvp) initial Newton iteration is not converging

 

P1 := plot([Y || (1 .. 3)], 0 .. 10, labels = [eta, (D(f))(eta)])

P2 := plot([YP || (1 .. 3)], 0 .. 10, labels = [eta, F(eta)])

plots:-display([P1, P2])

Error, (in plots:-display) expecting plot structures but received: [P1, P2]

 

``

 

Download unsteadyManjunatha.mw

For solving problem sets, I have a pdf template I created for myself that has a header with a blank for the class name, TA, professor, date, etc. In addition to this header, I had a margin on the left to scribble questions I had and to holepunch. 

 

I used to print out the template and write on the template and turn in that as my pset.

 

I am nowthinking of doing everything on the computer. Writing out all of the problem set on the computer. Combining stuff from maple, combining handwritten stuff from the computer using a digitizer. However I want to write it all on top of the my template that I created, which is a pdf file. I can turn the pdf into an image file if need be. 

 

What would be the easiest way to do what I want? To open a program that automatically sets that pdf as the template and easily lets me handwrite stuff I want and paste in maple code? 

 

Right now if I tried my idea, I would basically be constantly copying and pasting stuff from maple and my digitizer drawn pictures/equations into one file and it would be very clumsy.

 

Basically there are problems that I do partially on maple and I just want to unify all my work into one easy, printable file. 

I have two 6x1 Matrices which are the results of a calculation process in Maple. One with a set of equations and the other one with a set of variables: 

A := [0, f(x6), f(x6), 0, 0, f(x6)];

b := [x1, x2, x3, x4, x5, x6];

I'd like to solve the following system:

for i from 1 to 6 do

eq[i] := A[i] = b[i]:

od;

which is

eq[1] := 0 = x1;

eq[2] := f(x6) = x2;

eq[3] := f(x6) = x3;

...

 

If I type in the eqations manually, and execute "s := solve({eq[1],..,eq[6]},{x1,..,x6})" everything solves fine.

If I use the "for i from..." - structure, and execute "s := solve({eq[1],..,eq[6]},{x1,..,x6})" I get an empty space as solution.

I've tried to convert both matrices into lists, but it doesn't work.

Could it be that Maple doesnt know that x6 has to be the x6 in the function f(x6) ?

Can anyone tell me how to solve this please?

Hey Guys

I'm designing some stuff for controll theory

There I met following problem:

I want calculate the matrix A which is the product of X and G.

A is 6x6 matrix and all values in the diagonal  are ones, the rest is undefined and should be calculated

X is 6x6 diagonal matrix with the values X1...X6

and G is also 6x6 and have all these values.

 

now I'm stuck 'cause I haven't used Maple frequently (only some simple stuff up to now, nothing with matrices)

I'd really appreciate it, if someone can tell how to tackle this problem

Cheers

This is better explained with simple example. Suppose I have these 2 equations

a:='a';b:='b';x:='x';
eqs:=[3*a+4*b = 3*x, 5*a+7*b = 7*x];

What I want is to solve for (a/x) and (b/x) from the above, and not for "a" and "b".

Currently, I do this manually as follows. First divide both equations by 'x' to obtain the ratio. I had to do this manually as writing eqs/x gave expression which was hard to work with for what I want to do. I could not simplify it for what I wanted. So I typed this

eqs2:=[3*(a/x)+4*(b/x)=3,5*(a/x)+7*(b/x)=7];   %manually typed !

Now used algsubs to replace (a/x) by new variable z1, and replace (b/x) by new variable z2, then solve for z1,z2 (btw, I had to do algsubs one at a time. (need to look at this later, but not impotant)

algsubs(a/x=z1,eqs2);
algsubs(b/x=z2,%);
solve(%,{z1,z2});

       {z1=-7,z2=6}

Is there a way or function(s) to automate this. The hard part is telling Maple to use the ratio as new variable starting from set of equations.

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