Guys, need help with matlab: can't plot graph (differential equations)

Discussion in 'Programmer's Corner' started by Gudsaf, May 23, 2013.

  1. Gudsaf

    Thread Starter New Member

    May 23, 2013
    1
    0
    So, good day.
    I had problem with matlab: can't plot graph.
    Need to say u, i from Russia, maybe my language bad, so sorry))
    Maybe u can give advice - where (what forum) can help me?

    My equation:
    ??????.PNG
    My code:
    Code ( (Unknown Language)):
    1.  
    2. T = [0 5e-6];
    3. i0 = [0 0];
    4. [t, I] = ode45('qweq',T,i0);
    5.     % печатаем график i(t) / print i(t)
    6.     figure
    7.     plot(t,I(:,1))
    8.     grid on
    9.     legend('i(t)')
    10.     xlabel('t')
    11.     ylabel('i')
    12.     title('График зависимости тока от времени')
    13.     % печатаем график di/dt / print di/dt
    14.     figure
    15.     plot(t,I(:,2))
    16.     grid on
    17.     legend('di/dt')
    18.     xlabel('dt')
    19.     ylabel('di')
    20.     title('График зависимости di по dt')
    21.  
    Function:
    Code ( (Unknown Language)):
    1.  
    2. function F = qweq(t,I)
    3.     R0 = 2;
    4.     L = 1e-6;
    5.     C = 0.001e-6;
    6.     f = 1e6;
    7.     k = 8e10;
    8.     Um = 1;
    9.  
    10. w = 2*pi*f;
    11. R = R0*(1-k*I(1)^2);
    12.  
    13. F = zeros(2,1);
    14. F(1) = I(2);
    15. F(2) = ( Um*w*cos(w*t) - (1/C)*I(1) - R*I(2) )/L;
    16.  
    if i set k as 0, all ok. But in task k must be 8e10...
     
Loading...