Mahery Raharinjatovo wrote:
> Hello
> How can I solve this ?quation with Maxima ?
> 'diff(x,t)^2+5*x^2=8
> ------------------------------------------------------------------------
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The equation is not in a standard form that maxima expects.
You can put it in the form by solving for (x')^2 and taking the square
root. You get two equations, each of which are separable and Maxima
handles them just fine.
(%i9) display2d: false;
(%o9) false
(%i10) solve('diff(x,t)^2 + 5*x^2=8,'diff(x,t));
/* of course you can do this by hand */
(%o10) ['diff(x,t,1) = -sqrt(8-5*x^2),'diff(x,t,1) = sqrt(8-5*x^2)]
(%i11) ode2(%o10[1],x,t);
(%o11) -asin(5*x/(2*sqrt(10)))/sqrt(5) = t+%c
(%i12) ode2(%o10[2],x,t);
(%o12) asin(5*x/(2*sqrt(10)))/sqrt(5) = t+%c
-sen