Student Support Forum: 'Strange out put of DSolve' topicStudent Support Forum > General > Archives > "Strange out put of DSolve"

 < Previous Comment Help | Reply To Comment | Reply To Topic
 Author Comment/Response yehuda 02/03/13 04:03am Well, the fact that you get an answer from Maple is not a guarantee to a good answer Try adding a parameter to the ODE sol = DSolve[y'[x] == Tan[x + y[x]] + a, y[x], x] you get the result Solve[y[x] - (-Log[(1 + a) Cos[x + y[x]] + Sin[x + y[x]]] + (1 + a + a^2) (x + y[x]))/(2 + 2 a + a^2) == C[1], y[x]] Now check the limit of the left hand side within the Solve command Limit[sol[[1, 1]], a -> 0] returning 1/2 (-x + Log[Cos[x + y[x]] + Sin[x + y[x]]] + y[x]) That is, Log[Cos[x+y[x]] may be undefined if Cos[x+y[x]] equals zero What are the initial conditions ? say that for x==0 y[0] ==Pi/2, then what??? yehuda URL: ,

 Subject (listing for 'Strange out put of DSolve') Author Date Posted Strange out put of DSolve Shariel 02/02/13 11:50am Re: Strange out put of DSolve yehuda 02/03/13 04:03am
 < Previous Comment Help | Reply To Comment | Reply To Topic