I really appreciated your help, can you pls explain this command 

solve
  ( odetest
    ( genSol, [ode, bc])[2..3],
    [_C1, _C2]
  )[];

why you are taking [2,3] or its meaning

cVals:=solve(otest[-2..-1]); 

when i replaceabove command i could get an error

dear sir many thanks I have little confusion can you explain the second portion of your answer by talking some second order ode with BCS.