[交流] 用mathematica求解微分方程

如何用mathematica解这两个方程，并画出xi与t的曲线图，（其中yi=i*h,m = 2.4/10^16; \[Beta] = 5/10^5; G = 82*10^9; v = 0.29; b = 2.5/10^10; D= G/2 \[Pi]/(1 - v); h = 10 b; w = 0.1; n = 3; d = (n + 1)*h; ff=  0.5*10^9;(ff替代了方程里的一个字符) 求高手帮忙 我的解法是：方程里的f1与f2没有赋值成功，求高手帮忙 m = 2.4/10^16; \[Beta] = 5/10^5; G = 82*10^9; v = 0.29; b = 2.5/10^10; dd = G/2 \[Pi]/(1 - v); h = 10 b; w = 0.1; n = 3; d = (n + 1)*h; ff = 0.5*10^9; ClearAll[y, x, f2, f1]; y = Table[i*h, {i, n}]; f2 = Table[1, {n}]; f1 = Table[1, {n}]; For[i = 1, i <= n, i++, For[k = 1, k <= n, k++,   If[k == i, f2[[k]] = 0,    f2[[k]] = (x[t] -        x[k][t]) ((x[t] - x[k][t])^2 - (y[] -            y[[k]])^2)/((x[t] - x[k][t])^2 + (y[] -             y[[k]])^2)^2]]; f1[] = Apply[Plus, f2] ]; eqns = {Table[{m*x''[t] + \[Beta]*x'[t] - b*ff -       dd*b^2*f1[] +       dd*w*b*(x[t] y[]/(x[t]^2 + y[]^2) -          x[t]*(y[] - d)/(x[t]^2 + (y[] - d)^2)) == 0}, {i,      n}], Table[{x[0] == 0, x'[0] == 0}, {i, n}]}; NDSolve[eqns, Table[x, {i, n}], {t, 0, 0.1/10^9}] 360反馈意见截图1167302256711587.png 360反馈意见截图1699120795121125.png

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