On May 12, 2009, at 8:01 AM, Josephine Ame wrote:
> Hi
>
> I am trying to solve for numerical values but get symbolic answers.
> What am I doing wrong?
>
> My code:
>
> var('L,E,g')
> w=2*pi.n()
> u=1/12
> c_0 = 0.1
> j = 20
> de = 0.25
> al = list()
> AR=range (2,20,1)
> AR.reverse()
> print AR
> z=(g+u)^2 + j^2*w^2 -c_0*exp(-g*L)*(cos(j*w*L)*(g+u)-j*w*sin
> (j*w*L))/c_0*exp(-g*L)*(cos(j*w*L)* (g+u)-j*w*sin(j*w*L))
> for k in AR:
> P=c_0*exp(-g*L)*(cos(k*w*L)*(g+u)-k*w*sin(k*w*L))/((g+u)^2+
> k^2*w^2)
> Z = 1/P - 1 - (e^2/4)/z
> z = Z
> for E in range (0.00,2.00,de):
> for L in range (0,5,1):
> b=((g+u)-c_0*exp^(-g*L))/c_0*exp^(-g*L)
> solve([b==E^2/2*z],g)
> al.append(g)
>
> The result:
>
> [19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2]
> [g == 1/60]
> [g == (6 - 5*exp^g)/(60*exp^g)]
> [g == (6 - 5*exp^(2*g))/(60*exp^(2*g))]
> [g == (6 - 5*exp^(3*g))/(60*exp^(3*g))]
Use the "find root" command:
sage: solve(sin(x) - x == .1)
[x == (10*sin(x) - 1)/10]
sage: find_root(sin(x) - x == .1, -1, 1)
-0.85375015664086573
Type find_root? for help
- Robert
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