petres's profile - activity

I know, is there some possiblity to get rid of it. Should I write a bug report?

I have some problem with the legend, if I use the function graphics_array the entries of the legend box of the second plot appear twice. For example:

f(x) = sin(x)
g(x) = sin(2*x)
p1 = plot(f,(-2*pi,2*pi), legend_label="f")
p2 = plot(g,(-2*pi,2*pi), legend_label="g")
graphics_array((p1,p2))

What I am doing wrong, or how can I fix it? Thanks in advance

Thanks for the answer. It is a little disappointing. Is there a workaround? Maybe I could solve it in another way with Sage (using the e-function for matrizes ...) or by using directly the Maxima functions.. Without being able to solve linear differential equations I would have to switch to other math programms.

have the same error, have you a workaround?

Same holds also with ivar and ics arguments in desolve_system.

t = var('t')

y = function('y', t)
w = function('w', t)
p = function('p', t)

de1 = diff(y,t) == - 0.5*y - 0.9*p + 0.5*w
de2 = diff(w,t) ==           1.0*p + 0.7*w
de3 = diff(p,t) == + 0.5*y         - 0.3*w

desolve_system([de1, de2, de3], [y,p,w])

The function desolve_system stops with the error:

TypeError: unable to make sense of Maxima expression 'y(t)=ilt((200y(0)?g1090327^2+(-140y(0)+100w(0)-180p(0))?g1090327+60y(0)+54w(0)+226p(0))/(200?g1090327^3-40?g1090327^2+80?g1090327-83),?g1090327,t)' in Sage

Why? Thanks in advance!

bool(a*a < 1) works, its kind of strange.

var("a b")
assume(b > 0, b < 1, a > 0, a < 1)
bool(a*b < 1)

returns false, why?