How do you substitute into a contravariant index of a tensor say

T[~mu, nu]     ?

Nothing seems to work, I tried to subs(~mu=~1,T[~mu, nu]), subs(mu=1,T[~mu, nu]), and all permutations.

Substituting values into the covariant index works fine but not contravariant.

Surely it must be possible ?

restart:with(Physics):

Setup(dimension=3,coordinates=(X=[x,y,z])):

Define(Tp3[~alpha,~beta,~gamma],B[~lambda,mu],T3[~rho,~epsilon,~sigma]):

Tp3[~alpha,~beta,~gamma]=B[~alpa,rho]B[~beta,epsilon]B[~gamma,sigma]T3[~rho,~epsilon,~sigma]

SumOverRepeatedIndices of the expression does not do anything. Why?

Thanks for the answer.

What should I do to simplify eq13 further using trig sum identities?
Thank you for your help in advance,

Download test5.mw

how to determine lambda, m0, and n0? a_i, and c_i are constants and c^2 = c[1]^2 + c[2]^2. solA.mw

How do I solve equation (1) for omega, rho, lambda1, and lambda2? verif.mw

Download ode_exact.mw

How to find the exact solution of ODE's

can we express 'X' in terms of 'L'? i.e., X = (some const)*L XintoL.mw

Why does 'simplify' not work when calculating Eigenvectors? Further, how can we express (2) in a more simplified form by using 'simplify'?simplify.mw

I am trying to solve the following recursion for any n, given a constant c. Here is my code for it:

c := 2:

A[i] := rsolve({a(0) = 1/n, a(i) = ((n - i + 1)/(n - i) + 1/(c*(n - i)))*a(i - 1)}, a);

total := evala(Simplify(sum(eval(A[i], i=k), k=0..n-1)));
evalf(eval(total, n = 6));

For c = 1, I get a valid (and correct) output, however for c = 2 for example, rsolve is returning , which does not make sense when n is an integer. Is there something I am doing wrong here? Not sure why this is happening. Thanks!

im trying to write differential quadrature method i have successfully  generated system of equations using code but now im stuck with rk4 method to solve these equation in a loop kindly give me suggestions or modify the code

Download dq_code.mw

Multiplaction "dot" in Maple 2022 is way too small - causes errors.

e.g. two variables multiplied s*m ends up being sm a new variable as I cannot really see that there is a missing multiplication operator between the variables. This causes huge unnecessary errors.

Maple 9.x e.g had nice clear and big operators and this kind of error was avoided.

How can I undo this unfortunate regression in Maple 2022 to increase the size of multiplication operator and other operators, so that they actually becom visible and not just a little dot almost a pixel in size.

If I was a falcon (20x20)^infinity then this would have been ok, but I am not, I am human.

So how do I change this unfortunate regression so that these errors can be avoided.?

Why does Maple 2022 still have only a history of ten files in the Recents ?

It makes it very difficult to search for files you opened but only realised later you need, but then it is long out of the silly 10 history list.

Isnt there a way to make a perpetual list so that all files opened are saved chronologiacally against date, or... at least be able to increase the silly 10 recent files to something like 30

Thanks

In my code, why  does InitState(5,5) return only one element of the vector while Coherent(5) returns 5 elements of the vector?

Download test3.mw

How can I get the evaluation of integration inside if-statement?

Thanks for your help in advance,

Download SolnforProjectile_v3_3.mw

How to verify eq by using (2), (3) and (4)? Since lambda's, A's, B's and a are constant, but they appear as variables i.e., D[2](A1)..., (D[2] -> d/dt (derivative w.r.t 't')). Also q(n+1,t)- q(n,t) = a (const). Therefore, d/dt(q(n+1),t) - d/dt,(q(n,t))=0

verif_May24.mw