thanks for your attention.
1-i want to remove ''with(MTM): ''
2-i dont know this issue that there is difference between them.thus i must use only Bessel() in maple....
3-my mean is ''The Maple interpretation of diff(f(x), x, x) would be the second derivative of f(x) with respect to x''
4-I DONT KNOW this problem and i want use dsolve() in maple
5-i want to completely avoid loading the MTM package
6-yes ...i mean was S[m,n](t).
''In a similar way are you sure that 'xi', 'eta' ......''
i can say that , i want use different coefficient as xi[m] and eta[n] for dsolve eqaution.i confused where i should use non-indexable subscript and where use of it as indexable subscript??
please help me
thanks a lot