strange behavior in editor:
when you have written for example
((12)/(13)) and you want to delete 13 and
change to 24, it is not possible.
this occurs also in other cases.
Solve for u and v in the system of equations below
{ ((u′(e^(−2x) cos2x)+v′(e^(−2x) sin2x)=0)),((u′(e^(−2x) cos2x)′+v′(e^(−2x) sin2x)′=xe^(−2x) sinx)) :}
where u and v are functions of x