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nm 11483
November 05 2024
3 2

on my PC, windows 10, Maple 2024.2 has maple.mla of size 268 MB.

You can sort its content by size of each m file inside the mla. This is result of first top 10 entries by size

The 4th column, according to help under LibraryTools:-ShowContents  is the size in bytes of the m file.

Here is worksheet which displays all entries in Maple.mla sort by size.

> 

interface(version);

`Standard Worksheet Interface, Maple 2024.2, Windows 10, October 29 2024 Build ID 1872373`

> 

restart;
> 

library := FileTools:-JoinPath(["lib", "maple.mla"], base=mapledir):
> 

the_content:=LibraryTools:-ShowContents(library):
> 

#sort by large size to small size
the_content:=ArrayTools:-SortBy( convert(the_content,Matrix) ,'column', 4,'descending', 'inplace' ):
the_content[1..10];

Matrix(10, 4, {(1, 1) = "evalf/int/GaussLaguerreQuadratureTable.m", (1, 2) = [2024, 3, 1, 8, 35, 48], (1, 3) = 154783114, (1, 4) = 2376962, (2, 1) = "casesplit/K.m", (2, 2) = [2024, 3, 1, 8, 30, 34], (2, 3) = 57860403, (2, 4) = 159362, (3, 1) = "subtype.m", (3, 2) = [2024, 3, 1, 8, 52, 29], (3, 3) = 62029141, (3, 4) = 139356, (4, 1) = "RegularChains.m", (4, 2) = [2024, 3, 1, 8, 31, 30], (4, 3) = 173035257, (4, 4) = 100337, (5, 1) = "inttrans/mellin/bessel/table.m", (5, 2) = [2024, 3, 1, 8, 49, 53], (5, 3) = 60561441, (5, 4) = 88741, (6, 1) = "context/defaultconfig.m", (6, 2) = [2024, 3, 1, 8, 49, 23], (6, 3) = 25630911, (6, 4) = 77254, (7, 1) = "ifactor/PollardP1/tree.m", (7, 2) = [2024, 3, 1, 8, 26, 13], (7, 3) = 83287450, (7, 4) = 74717, (8, 1) = "inttrans/invmellin/bessel/table.m", (8, 2) = [2024, 3, 1, 8, 49, 47], (8, 3) = 138871406, (8, 4) = 68185, (9, 1) = "evalf/int/GaussLegendreQuadratureTable.m", (9, 2) = [2024, 3, 1, 8, 35, 48], (9, 3) = 139687979, (9, 4) = 60871, (10, 1) = "convert/Sum/from.m", (10, 2) = [2024, 3, 1, 8, 33, 51], (10, 3) = 80273108, (10, 4) = 57302})

> 

the_table :=Array(1..0):
the_table ,= ["m file name","size in bytes (4th column)","cummulative size in bytes"]:
total_size := 0:
for N from 1 to  LinearAlgebra:-RowDimension(the_content) do    
    current_size:=the_content[N,4]:
    total_size:= total_size+current_size:
    the_table ,= [the_content[N,1],current_size,total_size]:
    if N>20 then #remove this check to see all, as table becomes too large to show
       break;
    fi;
od:
the_table:=convert(the_table,listlist):
DocumentTools:-Tabulate(the_table,width=40,weights = [2, 1, 1]);

"Tabulate1"

> 

 


Download lib_size_nov_5_2024.mw

reply...

nm 11483
November 05 2024
3 1

Updated to add 2 columns , exact and approx solutions. ps also changed x values list. Note at x=1 we have division by zero in exact solution.

> 

restart;
> 

exact_sol:=1/(1-x);
approx_sol:=1 + x + 37/60*x^5 + 2/3*x^4 + 1/3*x^3 + x^2 + 2351/7560*x^9 + 781/1680*x^8 + 101/210*x^7 + 53/120*x^6 + 1/7*x^10 + 1091/23100*x^11 + 11/15600*x^13 + 11/1200*x^12;

1/(1-x)

1+x+(37/60)*x^5+(2/3)*x^4+(1/3)*x^3+x^2+(2351/7560)*x^9+(781/1680)*x^8+(101/210)*x^7+(53/120)*x^6+(1/7)*x^10+(1091/23100)*x^11+(11/15600)*x^13+(11/1200)*x^12

> 

the_table :=Array(1..0):
the_table ,= [x,"exact solution", "approximate solution","Abs Error","Relative Error"]:
data:=[seq(i,i=0..1,0.1)];
for item in data do
    current_exact_sol:=evalf(eval(exact_sol,x=item));
    current_approx_sol:=evalf(eval(approx_sol,x=item));
    current_error := abs(current_exact_sol-current_approx_sol);
    current_relative_error := current_error/current_exact_sol;
    the_table ,= [item,current_exact_sol,current_approx_sol,current_error ,current_relative_error]:
od:
the_table:=convert(the_table,listlist):
DocumentTools:-Tabulate(the_table,width=60):

[0, .1, .2, .3, .4, .5, .6, .7, .8, .9, 1.0]


Download error_table_nov_5_2024.mw

reply...

nm 11483
October 29 2024
1 1 
igcd(45,63)

     9

So it is (A)

reply...

nm 11483
October 26 2024
1 1

 is there a way to generate solutions to an ODE by producing specific parameters?

May be I am not answering the correct question. Why not do something similar to you question How-I-Can-Give-Assumption-To-A-ODE-Equation  where you setup the values in list and iterate over them?

btw, I assumed m->1^{-} means limit as m->1 from left.   some of these values when substituted into the ode and m is replaced by 1, give same ode!. You can add more parameters as needed.

> 

restart;
> 

data:=[ [P=m^2,Q=-(1+m^2),R=1],
        [P=1,Q=-(1+m^2),R=m^2],
        [P=-m^2,Q=2*m^2-1,R=1-m^2],
        [P=1,Q=2*m^2-1,R=-m^2*(1-m^2)],
        [P=1/4,Q=(m^2-2)/2,R=m^2/4],
        [P=m^2/4,Q=(m^2-2)/2,R=m^2/4]
        ]:
the_result :=Array(1..0):
the_result ,= [P,Q,R,"current ode","solution"]:
ode:=diff(F(xi),xi)^2=P*F(xi)^4+Q*F(xi)^2+R:
for item in data do
    current_ode:=limit(eval(ode,item),m=1,'left'):
    sol:=[dsolve(current_ode)]:
    the_result ,= [rhs(item[1]),rhs(item[2]),rhs(item[3]),current_ode,sol]:        
od:
the_result:=convert(the_result,listlist):
DocumentTools:-Tabulate(the_result,weights=[10,20,20,45,45],width=60):


 

Download ode_answer_oct_26_2024.mw


 

reply...

nm 11483
October 25 2024
4 13
> 

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

> 

data:=[[A,B],[0,B],[A,0],[0,0]]:
the_result :=Array(1..0):
ode:=diff(G(xi),xi)=G(xi)^2+A*G(xi)+B:
the_result ,= ["A","B","solution"]:

for item in data do
    eval(ode,[A=item[1],B=item[2]]):
    sol:=dsolve(%):
    the_result ,= [item[1],item[2],sol]:
od:
the_result:=convert(the_result,listlist):
DocumentTools:-Tabulate(the_result,weights=[10,10,100],width=30):
 

Download dsolve_oct_25_2024.mw

update

This version evaluates U=a0+a1*G(xi) after solving for G(xi) using current cases. And then verifies the U solution against the current updated F_ode.

May be this is what the question asks for?

> 

restart;
> 

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

> 

data:=[[A=A,B=B],[A=0,B=B],[A=A,B=0],[A=0,B=0]]:
the_result :=Array(1..0):
G_ode:=diff(G(xi),xi)=G(xi)^2+A*G(xi)+B:
F_ode := (-delta*eta^2 + alpha*eta)*diff(diff(U(xi), xi), xi) - U(xi)*(2*eta*gamma*theta*(delta*eta - alpha)*U(xi)^2 + eta^2*delta*k^2 + (-alpha*k^2 - 2*delta*k)*eta + 2*k*alpha + delta) = 0:
the_cases := [alpha = delta*(A^2*eta^2 - 2*eta^2*k^2 - 4*B*eta^2 + 4*eta*k - 2)/(A^2*eta - 2*eta*k^2 - 4*B*eta + 4*k),
             eta = eta,
             a[0] = -A/(2*gamma*theta*RootOf(_Z^2*gamma*theta + 1)),
             a[1] = RootOf(_Z^2*gamma*theta + 1)
             ]:
a0_original_value:=select(has,the_cases,a[0])[]:
a1_original_value:=select(has,the_cases,a[1])[]:
the_result ,= ["A","B",a0_original_value,a1_original_value,G(xi),U(xi)=a[0] + a[1]*G(xi),"odetest result"]:

for item in data do
    current_G_ode:=eval(G_ode,item):
    sol_G:=dsolve(current_G_ode):
    current_case := eval(the_cases,item):
    current_F_ode:=eval(F_ode,current_case):
    my_U_sol:= eval(a[0] + a[1]*G(xi),[op(current_case),sol_G]);
    was_verified:=odetest(U(xi)=my_U_sol,current_F_ode);
    a0_usesd :=rhs(select(has,current_case,a[0])[]);
    a1_usesd :=rhs(select(has,current_case,a[1])[]);
    the_result ,= [rhs(item[1]),rhs(item[2]),a0_usesd,a1_usesd,sol_G,my_U_sol,was_verified]:
od:
the_result:=convert(the_result,listlist):
DocumentTools:-Tabulate(the_result,weights=[10,10,50,50,100,100,20],width=80):
 


Download dsolve_oct_25_2024_V2.mw

reply...

nm 11483
October 20 2024
1 1

This is what I get in 2024.1.  Not sure if this is what you meant.

> 

M:=sin(x)/cos(x);
simplify(M);

sin(x)/cos(x)

tan(x)

> 

M:=1/sin(x);
simplify(M);

1/sin(x)

csc(x)

> 

M:=1/cos(x);
simplify(M);

1/cos(x)

sec(x)

> 

Q:=sqrt(beta/(B*cos(zeta*sqrt(-lambda))))

(beta/(B*cos(zeta*(-lambda)^(1/2))))^(1/2)

> 

simplify(Q) assuming lambda>0

(beta*sech(zeta*lambda^(1/2))/B)^(1/2)

 

 

Download trig_simplification.mw

reply...

nm 11483
October 15 2024
1 1

may be this is what you meant

> 

old_values := [alpha = 0.33101604, theta = -2.54098361, mu = 4.89071038, k = 5.0, A[1] = 2.70491803, a = 3.63387978];

[alpha = .33101604, theta = -2.54098361, mu = 4.89071038, k = 5.0, A[1] = 2.70491803, a = 3.63387978]

> 

new_values:=map(X->lhs(X)=MapleTA:-Builtin:-decimal(2,rhs(X)),old_values)

[alpha = .33, theta = -2.54, mu = 4.89, k = 5.00, A[1] = 2.70, a = 3.63]

> 

#or

> 

new_values:=map(X->lhs(X)=:-parse(sprintf("%.2f",rhs(X))),old_values)

[alpha = .33, theta = -2.54, mu = 4.89, k = 5.00, A[1] = 2.70, a = 3.63]

 

 

Download change_decimal.mw

Now use the new_values instead.

reply...

nm 11483
October 09 2024
1 2

set the ranges then it works like Matlab

> 

f:=x^(2*z)+y^(-2*y^(-z))+exp(-1/10*z^2)=1;
plots:-implicitplot3d(f,x=1.3..2,y=1.3..2,z=-2..-1.3,style=surface)
> 

 

x^(2*z)+y^(-2*y^(-z))+exp(-(1/10)*z^2) = 1

> 

 


As for the gridlines, this option does not seem to be supported for 3D plots in Maple. May be someone knows of a trick.

 

Download plot3d.mw

reply...

nm 11483
October 06 2024
1 1

This fixes two issues you had. you need to remove the O() from the series solution, and need to add [] around ode and the IC. But Maple can't solve the final pde analytically.  V 2024.1
 

> 

restart;
> 

ode0 := diff(xi^2*diff(theta[E](xi), xi), xi)/xi^2 = -theta[E](xi)^n;

(2*xi*(diff(theta[E](xi), xi))+xi^2*(diff(diff(theta[E](xi), xi), xi)))/xi^2 = -theta[E](xi)^n

> 

bc0 := theta[E](0) = 1, D(theta[E])(0) = 0;

theta[E](0) = 1, (D(theta[E]))(0) = 0

> 

base := dsolve([bc0, ode0], theta[E](xi), series);
base := convert(base,polynom);

theta[E](xi) = series(1-(1/6)*xi^2+((1/120)*n)*xi^4+O(xi^6),xi,6)

theta[E](xi) = 1-(1/6)*xi^2+(1/120)*n*xi^4

> 

pde1 := diff(xi^2*diff(psi(xi, mu), xi), xi)/xi^2 + diff((-mu^2 + 1)*diff(psi(xi, mu), mu), mu)/xi^2 = -psi(xi, mu)^n + v;

(2*xi*(diff(psi(xi, mu), xi))+xi^2*(diff(diff(psi(xi, mu), xi), xi)))/xi^2+(-2*mu*(diff(psi(xi, mu), mu))+(-mu^2+1)*(diff(diff(psi(xi, mu), mu), mu)))/xi^2 = -psi(xi, mu)^n+v

> 

bc1 := psi(0, mu) = 1, D[1](psi)(0, mu) = 0, D[2](psi)(0, mu) = 0, limit(psi(xi, mu), v = 0) = rhs(base);

psi(0, mu) = 1, (D[1](psi))(0, mu) = 0, (D[2](psi))(0, mu) = 0, psi(xi, mu) = 1-(1/6)*xi^2+(1/120)*n*xi^4

> 

psi(xi, mu)

psi(xi, mu)

> 

pdsolve([pde1, bc1],psi(xi, mu))
> 

pdsolve([pde1, bc1],psi(xi, mu),series)
> 

pdsolve(pde1,psi(xi, mu))
> 

 


 

Download Nonlinear_Elliptic_PDE_in_Spherical_Coordinate.mw

reply...

nm 11483
October 03 2024
0 0

Change your alpha to start from say 0.05 instead from 0 then it works.

You can see from your formula for M that you are dividing by alpha (inside the integral). Hence you can not use alpha=0 in the slider.
 

> 

params := {alpha = 1, gg = 0.1, k = 1, mu = 10, sigma = 5, w = 2};

{alpha = 1, gg = .1, k = 1, mu = 10, sigma = 5, w = 2}

> 

M := sqrt(-(gamma*(gamma*k*mu - 2*k*sigma)*k/(gamma*sigma - 1) + k^2)/alpha)*sinh(2*(gamma*k*(2*gamma*k*w + 2*k^2 + sigma^2)/(gamma*sigma - 1) - 2*k*sigma)*t/(gamma*sigma - 1))*exp(((2*gamma*k*w + 2*k^2 + sigma^2)*t/(gamma*sigma - 1) + sigma*x)*I)/(cosh(2*(gamma*k*(2*gamma*k*w + 2*k^2 + sigma^2)/(gamma*sigma - 1) - 2*k*sigma)*t/(gamma*sigma - 1)) - 1);

(-(gamma*(gamma*k*mu-2*k*sigma)*k/(gamma*sigma-1)+k^2)/alpha)^(1/2)*sinh(2*(gamma*k*(2*gamma*k*w+2*k^2+sigma^2)/(gamma*sigma-1)-2*k*sigma)*t/(gamma*sigma-1))*exp(((2*gamma*k*w+2*k^2+sigma^2)*t/(gamma*sigma-1)+sigma*x)*I)/(cosh(2*(gamma*k*(2*gamma*k*w+2*k^2+sigma^2)/(gamma*sigma-1)-2*k*sigma)*t/(gamma*sigma-1))-1)

> 

Explore(
     plot3d(abs(M), t = -5 .. 5, x = -10 .. 10,
        view = -10 .. 10, grid = [150, 150],
        color = [blue], style = surface, adaptmesh = false,
        size = [500, 500]),

     alpha = 0.05 .. 1.0,
     w = -5.0 .. 5.0,
     mu = -5.0 .. 5.0,
     sigma = -5.0 .. 5.0,
     k = -5.0 .. 5.0,

     placement = right);
> 

 


 

Download change_alpha.mw

 

 

reply...

nm 11483
September 25 2024
0 2

one way is to use allvalues

> 

eq1:=y=1/2*(x-5)^2-6;
eq2:=y=3*x-2;

y = (1/2)*(x-5)^2-6

y = 3*x-2

> 

sol:=solve([eq1,eq2],{x,y})

{x = RootOf(_Z^2-16*_Z+17), y = 3*RootOf(_Z^2-16*_Z+17)-2}

> 

allvalues(sol)

{x = 8-47^(1/2), y = 22-3*47^(1/2)}, {x = 8+47^(1/2), y = 22+3*47^(1/2)}

 

 

Download allvalues.mw

reply...

nm 11483
September 19 2024
3 2

 

 

> 

restart;
> 

mylist := [[sqrt(-5*x^2 - 5*x - 1) = -4*x - 1, {-1/3, -2/7}], [sqrt(-5*x^2 - 5*x - 1) = x + 1, {-1/2, -2/3}], [sqrt(-5*x^2 - 5*x - 1) = 4*x + 3, {-2/3, -5/7}], [sqrt(-5*x^2 - 5*x + 4) = -5*x + 3, {1/2, 1/3}], [sqrt(-5*x^2 - 4*x + 2) = -5*x + 2, {1/3, 1/5}], [sqrt(-5*x^2 - 4*x + 2) = -2*x + 1, {-1/3, 1/3}]]:
> 

toX:=s->latex(s,output=string):
s:="\\begin{enumerate}[label=\\arabic*)]\n":
for item in mylist do
    s:=cat(s,"\\item $",toX(item[1])," $\\hfill Answer: $",toX(item[2]),"$\n"):
od:
s:=cat(s,"\\end{enumerate}\n"):
    
> 

printf("%s",s)

\begin{enumerate}[label=\arabic*)]
\item $\sqrt{-5 x^{2}-5 x -1} = -4 x -1 $\hfill Answer: $\left\{-{\frac{2}{7}}, -{\frac{1}{3}}\right\}$
\item $\sqrt{-5 x^{2}-5 x -1} = x +1 $\hfill Answer: $\left\{-{\frac{2}{3}}, -{\frac{1}{2}}\right\}$
\item $\sqrt{-5 x^{2}-5 x -1} = 4 x +3 $\hfill Answer: $\left\{-{\frac{5}{7}}, -{\frac{2}{3}}\right\}$
\item $\sqrt{-5 x^{2}-5 x +4} = -5 x +3 $\hfill Answer: $\left\{{\frac{1}{2}}, {\frac{1}{3}}\right\}$
\item $\sqrt{-5 x^{2}-4 x +2} = -5 x +2 $\hfill Answer: $\left\{{\frac{1}{3}}, {\frac{1}{5}}\right\}$
\item $\sqrt{-5 x^{2}-4 x +2} = -2 x +1 $\hfill Answer: $\left\{-{\frac{1}{3}}, {\frac{1}{3}}\right\}$
\end{enumerate}

> 

 


 

Download to_latex_sept_19_2024.mw

reply...

nm 11483
September 16 2024
1 1

I do not think there is a way to tell dsolve to do this. But you can post-process the solution. Here is an example.

But pretty soon you will start having constants of integrations like c__100 and c__101 or may be c__5000 and so on depending on how many ODE's you plan to run in your loop. 
 

> 

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

> 

restart;
> 

fix_my_C:=proc(sol::`=`)::`=`;
   local C_used::set,my_C::set;
   C_used:= indets(sol,And(symbol, suffixed(c__, nonnegint))):
   my_C := map(X->X=`tools/genglobal`(c__),C_used):
   eval(sol,my_C);
end proc:
 
> 

`tools/genglobal`[1](c__, 1, :-reset); #do once at start
> 

ode:=diff(y(x),x$3)+y(x)=sin(x);
sol:=dsolve(ode);
sol:=fix_my_C(sol);

diff(diff(diff(y(x), x), x), x)+y(x) = sin(x)

y(x) = -(1/2)*cos(x)/((3^(1/2)-2)*(2+3^(1/2)))-(1/2)*sin(x)/((3^(1/2)-2)*(2+3^(1/2)))+c__1*exp(-x)+c__2*exp((1/2)*x)*cos((1/2)*3^(1/2)*x)+c__3*exp((1/2)*x)*sin((1/2)*3^(1/2)*x)

y(x) = -(1/2)*cos(x)/((3^(1/2)-2)*(2+3^(1/2)))-(1/2)*sin(x)/((3^(1/2)-2)*(2+3^(1/2)))+c__1*exp(-x)+c__2*exp((1/2)*x)*cos((1/2)*3^(1/2)*x)+c__3*exp((1/2)*x)*sin((1/2)*3^(1/2)*x)

> 

ode:=diff(y(x),x$2)+y(x)=sin(x);
sol:=dsolve(ode);
sol:=fix_my_C(sol);

diff(diff(y(x), x), x)+y(x) = sin(x)

y(x) = sin(x)*c__2+cos(x)*c__1+(1/2)*sin(x)-(1/2)*cos(x)*x

y(x) = sin(x)*c__5+cos(x)*c__4+(1/2)*sin(x)-(1/2)*cos(x)*x

> 

ode:=diff(y(x),x)+y(x)=sin(x);
sol:=dsolve(ode);
sol:=fix_my_C(sol);

diff(y(x), x)+y(x) = sin(x)

y(x) = -(1/2)*cos(x)+(1/2)*sin(x)+c__1*exp(-x)

y(x) = -(1/2)*cos(x)+(1/2)*sin(x)+c__6*exp(-x)

> 

ode:=diff(y(x),x$5)+y(x)=0;
sol:=dsolve(ode);
sol:=fix_my_C(sol);

diff(diff(diff(diff(diff(y(x), x), x), x), x), x)+y(x) = 0

y(x) = c__1*exp(-x)-c__2*exp((-(1/4)*5^(1/2)+1/4)*x)*sin((1/4)*2^(1/2)*(5+5^(1/2))^(1/2)*x)-c__3*exp(((1/4)*5^(1/2)+1/4)*x)*sin((1/4)*2^(1/2)*(5-5^(1/2))^(1/2)*x)+c__4*exp((-(1/4)*5^(1/2)+1/4)*x)*cos((1/4)*2^(1/2)*(5+5^(1/2))^(1/2)*x)+c__5*exp(((1/4)*5^(1/2)+1/4)*x)*cos((1/4)*2^(1/2)*(5-5^(1/2))^(1/2)*x)

y(x) = c__7*exp(-x)-c__8*exp((-(1/4)*5^(1/2)+1/4)*x)*sin((1/4)*2^(1/2)*(5+5^(1/2))^(1/2)*x)-c__9*exp(((1/4)*5^(1/2)+1/4)*x)*sin((1/4)*2^(1/2)*(5-5^(1/2))^(1/2)*x)+c__10*exp((-(1/4)*5^(1/2)+1/4)*x)*cos((1/4)*2^(1/2)*(5+5^(1/2))^(1/2)*x)+c__11*exp(((1/4)*5^(1/2)+1/4)*x)*cos((1/4)*2^(1/2)*(5-5^(1/2))^(1/2)*x)

> 

ode:=diff(y(x),x$2)+y(x)=sin(x)+1;
sol:=dsolve(ode);
sol:=fix_my_C(sol);

diff(diff(y(x), x), x)+y(x) = sin(x)+1

y(x) = sin(x)*c__2+cos(x)*c__1+(1/2)*sin(x)+1-(1/2)*cos(x)*x

y(x) = sin(x)*c__13+cos(x)*c__12+(1/2)*sin(x)+1-(1/2)*cos(x)*x

> 

 


 

Download different_C_for_each_dsolve.mw

reply...

nm 11483
September 15 2024
3 1

If you convert it to poly then it works. The command is convert(p,polynom)

> 

p := asympt(x*1/(1 - a*x - b*x^2), x);
p:=convert(p,polynom);

-1/(b*x)+a/(b^2*x^2)-(1/b+a^2/b^2)/(b*x^3)-(-a/b^2-(a^2+b)*a/b^3)/(b*x^4)-((a^2+b)/b^3+a^2*(a^2+2*b)/b^4)/(b*x^5)+O(1/x^6)

-1/(b*x)+a/(b^2*x^2)-(1/b+a^2/b^2)/(b*x^3)-(-a/b^2-(a^2+b)*a/b^3)/(b*x^4)-((a^2+b)/b^3+a^2*(a^2+2*b)/b^4)/(b*x^5)

> 

coeff(p,1/x)

-1/b

 

 

Download coeffs.mw

reply...

nm 11483
September 14 2024
1 6

DESol in solution really means there is no closed form solution. At least Maple could not find one.

You did not give the input you used so can't verify.

But you can always use something like select or evalindets to pick these out. Below worksheet showing how. Maple 2024.1 on windows

> 

interface(version);

`Standard Worksheet Interface, Maple 2024.1, Windows 10, June 25 2024 Build ID 1835466`

> 

ode:=diff(y(x),x)-y(x)*a-b*y(x)^2=f(x);
sol:=dsolve(ode);

diff(y(x), x)-y(x)*a-b*y(x)^2 = f(x)

> 

my_sol := DESol( ode, y(x) );

DESol({diff(y(x), x)-y(x)*a-b*y(x)^2-f(x)}, {y(x)})

> 

#to extract just first argument of DESol
evalindets(my_sol,'specfunc'(anything,DESol),F->op(1,F))

{diff(y(x), x)-y(x)*a-b*y(x)^2-f(x)}

> 

#to extract all arguments
evalindets(my_sol,'specfunc'(anything,DESol),F->op(1..,F))

{diff(y(x), x)-y(x)*a-b*y(x)^2-f(x)}, {y(x)}

> 

 


 

Download pick_DESol_argument.mw

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