Items tagged with solve

Here is one that the students generated which caused confusion. 

a := 0.76;
eq1 := 2*cot(a*sqrt(2*E)) = (2*E-5.4)/(sqrt(E*(5.4-E));
solve(eq1, E)

And the results are: 0., 4.411954070, 2.423743792

The problem is with the second answer because it does not exist. If we plot the LHS and the RHS of eq1 vs E where E=0..5.4

plot([2*cot(0.76*sqrt(2*E)), (2*E-5.4)/sqrt(E*(5.4-E))], E=0..5.4, -3..3)

And it gets more interesting, if we calculate:

solve(evalf(eq1), E)

The answers are: 0., 2.423743793, 14.33807304+27.39159712*I

where the 3rd answer is again incorrect.

Finally, if a = 0.8 or larger, the incorrect answers disappear. 

Note - fsolve does handle this problem correctly. And despite my attempts to remind them to use fsolve, they see the solve command as the universal truth. Apparently this will be another teaching moment for next year.

So any thoughts about why this happens and why there is a difference in the outcomes between 0.76 and 0.8 for the value of a?

 

I want to calculate the ratio of the length of day and night for every latitude on earth ?
but i confused on using Maple in a wise way for finding the formula !
this is my demonstration :

shekofte000.mw
 

Equations

 

the grat circle that divides the earth's surface into two dark and bright sides

[sin(t)*cos(tilt), cos(t), sin(t)*sin(tilt)]

[sin(t)*cos(tilt), cos(t), sin(t)*sin(tilt)]

(1.1)

circle of revolving of a point on earth in 24 hours

[sin(t)*cos(Latitude), cos(t)*cos(Latitude), sin(Latitude)]

[sin(t)*cos(Latitude), cos(t)*cos(Latitude), sin(Latitude)]

(1.2)

Visualization of dark and bright side the of earth

 

Explore(plots[display](plots[spacecurve]({[sin(t)*cos(tilt), cos(t), sin(t)*sin(tilt), color = red], [sin(t)*cos(Latitude), cos(t)*cos(Latitude), sin(Latitude), color = blue]}, t = 0 .. 2*Pi, scaling = constrained, thickness = 4, labels = [x, y, Latitudez], labeldirections = [horizontal, horizontal, vertical], axes = frame), plottools[rotate](plottools[hemisphere]([0, 0, 0], 1, capped = false, color = green, grid = [10, 10], style = surface), 0, tilt, 0), plottools[rotate](plottools[hemisphere]([0, 0, 0], 1, capped = false, color = black, grid = [10, 10], style = surface), 0, Pi+tilt, 0)), parameters = [tilt = 0 .. Pi, Latitude = -(1/2)*Pi .. (1/2)*Pi], initialvalues = [tilt = (1/2)*Pi+.409, Latitude = 1.16])

``


 

Download shekofte000.mw

 

Can somebody execute this code on a powerful comp and report the result in MaplePrimes? That would be kind of her/him.


 

RealDomain:-solve(a^2+b^2+c^2+a*b+a*c+b*c-  (a+b-c)*sqrt(2*a*b+a*c+b*c)-(a+c-b)*sqrt(a*b+2*a*c+b*c)-(b+c-a)*sqrt(a*b+a*c+2*b*c));

Error, (in assuming) when calling '`resultant/modular2`'. Received: 'Maple was unable to allocate enough memory to complete this computation.  Please see ?alloc'

 

``


 

Download want_for_execution.mw

hi.how i can solve or fsolve this equations?

i can not with fsolve?

thanks alot

SOLVE.mw


Maple Worksheet - Error

Failed to load the worksheet /maplenet/convert/SOLVE.mw .
 

Download SOLVE.mw

 

I'm trying to solve this integral, but maple does not show any result.

f := GAMMA(phi)*y^(mu*phi-1)*(1-y)^((1-mu)*phi-1)/(GAMMA(mu*phi)*GAMMA((1-mu)*phi))
int(log(1-y)*f, y = 0 .. 1) assuming phi >0 and 0<mu<1

What is the problem? Is there any way to solve this integral?

Hi all,

I have this equation that I can not get all solutions symbolically:

restart:

eq1 := cos(lambda*ln(r1))*cos(lambda*ln(r2))+sin(lambda*ln(r1))*sin(lambda*ln(r2))-1 = 0:

solve(eq1, lambda, allsolutions) assuming r1>0, r2>0, r2>r1

when r1:=1: r2:=2: I get the solution

2*Pi*Z/ln(2)

when r1:=1.1: and r2:=2.1: # no solutions

How to get symbolique solution

Thanks

 

 

Hello!

I am trying to solve several equations for some mechanics problem.
I made the following lines with variables: Az, Bz, Dz, Dx, Ma.
The equations are showed in the image below. I can use either Md equation or Mb to solve the problem, but using both is not allowed. I tried to solve the equations with the solve function, but cant find any answer though there should be?



Thank you in advance :)

Part of my research involves finding solutions to polynomial equations in several variables. Presently, I'm using Maple to both generate and solve these systems. With what I'll call a particular type of system the solve function returns several solutions, one of which has a particular variable free and the others where this variable is the root of a polynomial. By finding the roots of the polynomial, I can see that these solutions simply correspond to the solutions where the parameter is free.

So I'm trying to understand why this happens. Using the option dropmultiplicity=true has no effect, and there are no other details that I could find in the documentation. This question is ill-posed, I know, but any help would be appreciated.

hi...why solve for this equation dos not answer?

thanks

4.mw
 

restart; dsys3 := {diff(w(x), x, x, x, x, x, x)+diff(w(x), x, x, x, x)+diff(w(x), x, x)+(1-2)*w(x) = -90, w(0) = 0, w(1) = 0, ((D@@1)(w))(0) = 0, ((D@@1)(w))(1) = 0, ((D@@2)(w))(0) = 0, ((D@@2)(w))(1) = 0}; dsol5 := dsolve(dsys3, numeric, abserr = .1, output = array([.5]))

array( 1 .. 2, 1 .. 1, [( 1, 1 ) = (array( 1 .. 7, [( 1 ) = (x), ( 2 ) = (w(x)), ( 3 ) = (diff(w(x), x)), ( 4 ) = (diff(diff(w(x), x), x)), ( 5 ) = (diff(diff(diff(w(x), x), x), x)), ( 6 ) = (diff(diff(diff(diff(w(x), x), x), x), x)), ( 7 ) = (diff(diff(diff(diff(diff(w(x), x), x), x), x), x))  ] )), ( 2, 1 ) = (array( 1 .. 1, 1 .. 7, [( 1, 7 ) = (HFloat(-1.3899459757465982e-7)), ( 1, 3 ) = (HFloat(4.5022670883498417e-8)), ( 1, 1 ) = (.5), ( 1, 6 ) = (HFloat(2.2858770405958895)), ( 1, 5 ) = (HFloat(2.6615438731474126e-8)), ( 1, 4 ) = (HFloat(-0.04747952956114616)), ( 1, 2 ) = (HFloat(0.0019672907400671725))  ] ))  ] )

(1)

"restart;w(x):=C1* (sinh(x))+C2* (cosh(x))+C3 *(sin(x))+C4 *(cos(x))+C5 *(sin(x))+C6 *(cos(x))+90"

proc (x) options operator, arrow; C1*sinh(x)+C2*cosh(x)+C3*sin(x)+C4*cos(x)+C5*sin(x)+C6*cos(x)+90 end proc

(2)

A1 := evalf(subs(x = 0, w(x)))

90.+1.*C2+1.*C4+1.*C6

(3)

A2 := evalf(subs(x = 1, w(x)))

1.175201194*C1+1.543080635*C2+.8414709848*C3+.5403023059*C4+.8414709848*C5+.5403023059*C6+90.

(4)

A3 := evalf(subs(x = 0, diff(w(x), x)))

1.*C1+1.*C3+1.*C5

(5)

A4 := evalf(subs(x = 1, diff(w(x), x)))

1.543080635*C1+1.175201194*C2+.5403023059*C3-.8414709848*C4+.5403023059*C5-.8414709848*C6

(6)

A5 := evalf(subs(x = 0, diff(w(x), x, x, x)))

1.*C1-1.*C3-1.*C5

(7)

A6 := evalf(subs(x = 1, diff(w(x), x, x, x)))

1.543080635*C1+1.175201194*C2-.5403023059*C3+.8414709848*C4-.5403023059*C5+.8414709848*C6

(8)

solve({A1, A2, A3, A4, A5, A6}, {C1, C2, C3, C4, C5, C6})

``

solve*{A5, A6, C1, C2, C3, C4, C5, C6, 1.*C2+1.*C4+1.*C6, 1.*C2*upsilon^2-1.*C4*kappa^2-1.*C6*varsigma^2, C1*sinh(upsilon)+C2*cosh(upsilon)+C3*sin(kappa)+C4*cos(kappa)+C5*sin(varsigma)+C6*cos(varsigma), C1*upsilon^2*sinh(upsilon)+C2*upsilon^2*cosh(upsilon)-1.*C3*kappa^2*sin(kappa)-1.*C4*kappa^2*cos(kappa)-1.*C5*varsigma^2*sin(varsigma)-1.*C6*varsigma^2*cos(varsigma)}

(9)

``

``

``


 

Download 4.mw

 

Up to http://www.maplesoft.com/support/help/Maple/view.aspx?path=solve&term=solve

• 

If the solve command does not find any solutions, then if the second argument is a name or set of names, then the empty sequence (NULL) is returned; if the second argument is a list, then the empty list is returned. This means that there are no solutions, or the solve command cannot find the solutions. In the second case, a warning is issued, and the global variable_SolutionsMayBeLost is set to true.

 Let us consider 

solve({x > -Pi, (tan(x)-tan(x)^2)^2-cos(x+4*tan(x)) = -1, x < Pi}, [x]);
                               []

We see the command omits the solution x=0 without any warning. It should be noticed that Mathematica solves it, outputting

{{x -> 0}, {x -> 0}}

and the warning

Solve::incs: Warning: Solve was unable to prove that the solution set found is complete.

One may draw a conclusion on her/his own.

 

Hi,

I want to solve 2 linear equations in p[1] and p[2] 

eq3 = -(1/8)*(x^2+y^2+((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)+omega[1]-omega[2])*(x^2*p[1]+2*x*y*p[2]-y^2*p[1]-((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)*p[1]+omega[1]*p[1]-omega[2]*p[1])/(y^2*x*(omega[1]-omega[2])) - P[1];
eq4 = -(1/8)*(x^2*p[1]+2*x*y*p[2]-y^2*p[1]+((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)*p[1]+omega[1]*p[1]-omega[2]*p[1])*(x^2+y^2-((x^2+y^2)^2+2*(omega[1]-omega[2])*(x^2-y^2)+(omega[1]-omega[2])^2)^(1/2)+omega[1]-omega[2])/(y^2*(omega[1]-omega[2])*x) - P[2]

solve({eq3,eq4},{p[1],p[2]});

I don't receive any answer. Why?

 

hi there,

this is my first post here, and first time using maple

I do have trigonometric system of equations, and I like to solve for thetas(1-5).

please help me out( how do I inpu them in maple) and how to solve them? 

how to configure maple to show every steps it run when solve a equation or system?

if so,

can i run the steps again and return the same result as a solve function do?

Am trying to valid a research work done by kuiken(1968)

Kuiken_(1968).pdf

where we have this two eauations:

restart;
Digits := 35;
with(ODETools);
with(student);
with(plots);
inf := 4;
equ1 := diff(f[0](eta), `$`(eta, 3))+theta[0](eta);
equ2 := diff(theta[0](eta), `$`(eta, 2))+3*f[0](eta)*(diff(theta[0](eta), eta));
Bcs1 := f[0](0) = 0, (D(f[0]))(0) = 0, theta[0](0) = 1, theta[0](inf) = 0, (D(D(f[0])))(inf) = 0;
S1 := dsolve({Bcs1, equ1, equ2}, {f[0](eta), theta[0](eta)}, type = numeric, method = bvp[midrich]);
proc(x_bvp)  ...  end;
S1(0);
[                            d                   
[eta = 0., f[0](eta) = 0., ----- f[0](eta) = 0., 
[                           deta                 

    d   /  d            \                                          
  ----- |----- f[0](eta)| = 0.82449782146165697398999365896678734, 
   deta \ deta          /                                          

  theta[0](eta) = 1.0000000000000000000000000000000000, 

    d                                                         ]
  ----- theta[0](eta) = -0.71098574970825563256340736114251047]
   deta                                                       ]
S1(inf);
[                                                            
[eta = 4., f[0](eta) = 1.7815670728545914261072119522795076, 
[                                                            

    d                                                      
  ----- f[0](eta) = 0.51061876174095320088291844433043562, 
   deta                                                    

    d   /  d            \                           
  ----- |----- f[0](eta)| = 0., theta[0](eta) = 0., 
   deta \ deta          /                           

    d                                                             
  ----- theta[0](eta) = -0.000054818176138173095945902421930470836
   deta                                                           

  ]
  ]
  ]
 

 

Pls, I need to find the function of the limit of f[0](eta) at eta tend to infinity. checked equation 45 of the attached document and for the two equation pls checked equation 36 and 37 for the ODE equation solved above.

Kuiken_solution for equation 36 and 37.pdf

Pressure_loss.mw

Hey all, could someone pls help me with how i can setup the equation for f in my worksheet. It should look like v and Rey with 45 data points. I've tried alot but i can't seem to solve it mysefl. Is it because i solve and map at the same time?

Thanks

1 2 3 4 5 6 7 Last Page 1 of 52