[Maxima] Any light ?

[Dan]

On Sat, 5 May 2012, aishen at free.fr wrote:

> assume(omega > 0)$
> ode2( 'diff(y, t, 2) + omega^2* y= 0, y, t );
> ic2(%, t = 0, y = a, 'diff(y,t) = 0);
>
> y=a*cos(omega*t) is the answer ...
>
> I am trying to get a sin ...  instead a cos but I can't !!!

The 'diff(y,t) term in your ic2 command imposes a boundary condition
that the sine can satisfy only by having a zero coefficient, i.e. by
being absent from the answer.