## how to express tanh(x) and tanh(x+1)?...

series(1/(1-x), x=0);
can be express as sum(x^y,y=0..infinity)

series(tanh(x), x=0);
how to express tanh(x) and tanh(x+1)?

is there any function and procedure to generate x^y these kind of result?

## how to plot this function?...

g2 := arctanh((exp(2*y)+sqrt((exp(2*y))^2+exp(2*y)))/exp(2*y)-1)-1;
singular(g2);
plot(g2, y=-5..5);

## How to put a geometric object in another geometric...

Assume I had a 2D line

how to put and draw this line into a new geometric world defined by patch?

## how to find a patch in maple?...

how to find back a patch in maple from Pi+GaussCurvature*Area(triangle) = Pi

restart:
with(LinearAlgebra):
EFG := proc(X)
local Xu, Xv, E, F, G;
Xu := <diff(X[1],u), diff(X[2],u), diff(X[3],u)>;
Xv := <diff(X[1],v), diff(X[2],v), diff(X[3],v)>;
E := DotProduct(Xu, Xu, conjugate=false);
F := DotProduct(Xu, Xv, conjugate=false);
G := DotProduct(Xv, Xv, conjugate=false);
simplify([E,F,G]);
end proc;

UN := proc(X)
local Xu,Xv,Z,s;
Xu := <diff(X[1],u), diff(X[2],u), diff(X[3],u)>;
Xv := <diff(X[1],v), diff(X[2],v), diff(X[3],v)>;
Z := CrossProduct(Xu,Xv);
s := VectorNorm(Z, Euclidean, conjugate=false);
simplify(<Z[1]/s|Z[2]/s|Z[3]/s>,sqrt,trig,symbolic);
end:

lmn := proc(X)
local Xu,Xv,Xuu,Xuv,Xvv,U,l,m,n;
Xu := <diff(X[1],u), diff(X[2],u), diff(X[3],u)>;
Xv := <diff(X[1],v), diff(X[2],v), diff(X[3],v)>;
Xuu := <diff(Xu[1],u), diff(Xu[2],u), diff(Xu[3],u)>;
Xuv := <diff(Xu[1],v), diff(Xu[2],v), diff(Xu[3],v)>;
Xvv := <diff(Xv[1],v), diff(Xv[2],v), diff(Xv[3],v)>;
U := UN(X);
l := DotProduct(U, Xuu, conjugate=false);
m := DotProduct(U, Xuv, conjugate=false);
n := DotProduct(U, Xvv, conjugate=false);
simplify([l,m,n],sqrt,trig,symbolic);
end proc:

GK := proc(X)
local E,F,G,l,m,n,S,T;
S := EFG(X);
T := lmn(X);
E := S[1];
F := S[2];
G := S[3];
l := T[1];
m := T[2];
n := T[3];
simplify((l*n-m^2)/(E*G-F^2),sqrt,trig,symbolic);
end proc:

sph := <f(u,v)|g(u,v)|h(u,v)>;
cur := GK(sph);
X := sph;
Xu := <diff(X[1],u), diff(X[2],u), diff(X[3],u)>;
Xv := <diff(X[1],v), diff(X[2],v), diff(X[3],v)>;
Z := CrossProduct(Xu,Xv);
AreaTriangle := int(int(Z[1]^2+Z[2]^2+Z[3]^2,v=-Pi/2..Pi/2),u=0..2*Pi);
dsolve(Pi+cur*AreaTriangle = Pi, [f(u,v),g(u,v),h(u,v)]);

## how to dsolve for x(t) in this case?...

in the steps below, it is not fluent to do, and appear diff(1,t)

KineticEnergy := 1/2*m*diff(x(t), t)^2;
PotentialEnergy := subs(x=x(t),int((1/R^2)^2,x));
Action := KineticEnergy - PotentialEnergy;
AA := diff(Action,x(t)) - diff(diff(Action, diff(x(t),t)),t) = 0 <-------- Dsolve this
AA := eval(subs(diff(1,t)=0,diff(Action,x(t))) - Diff(subs(p=Diff(x(t),t),diff(subs(Diff(x(t),t)=p, Action), p)),t)) = 0
dsolve(AA, x(t));

Where R is constant

## how to dsolve for this equation?...

this equation is complicated

how to dsolve for this equation for function f ?

f(t,x,diff(x,t)) - f(t,x,p) - (diff(x,t)-p)*diff(f(t,x,p), p) = tan(t)

## how to solve this system?...

updated:
P := evalm(p2 + c*vector([cos(q1+q2+q3), sin(q1+q2+q3)]));

restart:
with(Groebner):
p1 := vector([a*cos(q1), a*sin(q1)]);
p2 := evalm(p1 + b*vector([cos(q1+q2), sin(q1+q2)]));
P := evalm(p2 + c*vector([cos(q1+q2+q3), sin(q1+q2+q3)]));
Pe := map(expand, P);
A := {cos(q1) = c1, sin(q1) =s1, cos(q2)=c2, sin(q2)=s2, cos(q3)=c3, sin(q3)=s3};
P := subs(A, op(Pe));
F1 := [x - P[1], y - P[2], s1^2+c1^2-1, s2^2+c2^2-1, s3^2+c3^2-1 ];
F2 := subs({a=1, b=1, c=1}, F1);

g2 := Basis(F2, plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[1], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[2], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[3], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[4], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[5], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[6], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[7], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[8], plex(c3, s3, c2, s2, c1, s1));
LeadingTerm(g2[9], plex(c3, s3, c2, s2, c1, s1));

1, c1
2       2    2   2
16 y  + 16 x , s1  s2
2
8 x, c1 s2
2      2    2
2 y  + 2 x , s1  c2
2 x, c1 c2
3            2
2 x  - 2 x + 2 y  x, s2 c2
2
1, c2
2 x, s3
2, c3
originally i think
g2[1], g2[7], g2[9] have single variables c1, c2, c3 respectively
can be used to solve system

but without x and y, these equations can not be used
if choose leading term has x and y , but there is no single variable s1 or c1.

originally expect solve as follows
g2spec := subs({x=1, y=1/2}, [g2[3],g2[5],g2[6]]);
S1 := [solve([g2spec[1]])];
q1a := evalf(arccos(S1[1]));
q1b := evalf(arccos(S1[2]));
S2 := [solve(subs(s1=S1[1], g2spec[2])), solve(subs(s1=S1[2], g2spec[2])) ];
q2a := evalf(arccos(S2[1]));
q2b := evalf(arccos(S2[2]));
S3 := [solve(subs(s1=S2[1], g2spec[2])), solve(subs(s1=S2[2], g2spec[2])) ];
q2a := evalf(arccos(S3[1]));
q2b := evalf(arccos(S3[2]));

## Error, (in limit/dosubs) invalid input: `limit/dos...

f := -ln(-1-ln(exp(x)))+ln(-ln(exp(x)))-Ei(1, -1-ln(exp(x)))+Ei(1, -ln(exp(x)))
solve(limit(diff((subs(x=q, f)-f),h), h=0) = f, q);
limit(diff((subs(x=x*h, f)-f),h), h=0);
Error, (in limit/dosubs) invalid input: `limit/dosubs` uses a 3rd argument, newx, which is missing

guess an operator called Lee, Lee(f, x) = f

solve(limit(diff((subs(x=q, f)-f),h), h=0) = f, q);

suspect q = x*h or q=x*f

limit(diff((subs(x=x*h, f)-f),h), h=0);
Error, (in limit/dosubs) invalid input: `limit/dosubs` uses a 3rd argument, newx, which is missing

limit(diff((subs(x=f*h, f)-f),h), h=0);
Error, (in depends/internal) invalid input: `depends/internal` uses a 2nd argument, x, which is missing

## how to solve this system?...

sys1:=-.736349402144656384 = -1.332282598*10^12*(-.99999999999999966)^po1-1.332282598*10^12*(-.99999999999999966)^po2-.735533633151605248*Resid;

sys2:=.326676717828940144 = 1.331567176*10^12*(-.99999999999999966)^po1+1.331567176*10^12*(-.99999999999999966)^po2+.325144093024965720*Resid;

sys3:=.590327283775080036 = -1.072184073*10^9*(-.99999999999999966)^po1-1.072184073*10^9*(-.99999999999999966)^po2+.589610307487437146*Resid;

Minimize(sys1, {sys2,sys3},assume = nonnegative);

complex value encountered;

## how to calculate basis for this basis...

how to calculate basis <1,4,0>, <1,0,4> for eigenvalue 2;

how to calculate basis <1,0,1> for eigenvalue -1;

with(LinearAlgebra):
A := Matrix([[-2,1,1],[0,2,0],[-4,1,3]]);

sys1 := Eigenvalues(A)[1]*IdentityMatrix(3)-A;

sys1 := Eigenvalues(A)[2]*IdentityMatrix(3)-A;
sys1 := Eigenvalues(A)[3]*IdentityMatrix(3)-A;

B:=[<sys1[1,1],sys1[2,1],sys1[3,1]>,<sys1[1,2],sys1[2,2],sys1[3,2]>,<sys1[1,3],sys1[2,3],sys1[3,3]>,<0,0,0>];
LinearAlgebra:-Basis(B);

but not <1,4,0>, <1,0,4> for eigenvalue 2

## invalid input: LinearAlgebra:-Basis expects its 1s...

invalid input: LinearAlgebra:-Basis expects its 1st argument, V, to be of type {Vector, set(Vector), list(Vector)

A:=<<5,5,5>|<1,2,3>|<-5,1,2>>;
Basis(A);

## what are the equivalent maple command in python?...

1.op(0,Expr) , op(1,Expr)

2. indets(eq1,{string,name})

3. type(varlist[ii], function)

## how to find back the input if slope is this?...

sph := <R*cos(u)*cos(v)|R*sin(u)*cos(v)|R*sin(v)>;
GK(sph); #Gauss Curvature
MK(sph); #Mean Curvature

how to find sph if slope is tan(u) ?

## how to guess the variables?...

A. how to find xx1,xx2,xx3,yy1,yy2,yy3 that
Determinant(Matrix([[xx1,yy1,1],[xx2,yy2,1],[xx3,yy3,1]])) =(1/2)*aa*d*s*u+(1/2)*aa*d*s*a*t+(1/2)*d*v*u*t+(1/4)*d*v*a*t^2;

B. how to find x1,x2,x3,x4,y1,y2,y3,y4 that expand(
(x2 - x1)*(y4 - y3) - (y2 - y1)*(x4 - x3)) = (1/2)*d*s*aa*v+(1/2)*d*aa*v*u*t+(1/4)*d*aa*v*a*t^2+(1/2)*aa*d*s*u+(1/2)*aa*d*s*a*t+(1/2)*d*u^2*t+(3/4)*d*u*a*t^2+(1/4)*d*a^2*t^3;

## can this be a solution set?...

v=u+at                      (1)
s=u*t+1/2*a*t^2        (2)

below 3 equations, can substitute  (1)  into it to form (2)
s=1/2*(u+v)*t       (3)
v^2=u^2+2*a*s    (4)
s=v*t-1/2*a*t^2    (5)

can these 5 equations be considered as a solution set of solve function?

or

is only first 2 equations be a solution set?

if so, number of equations less than 5 variables, is there something missing?

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