Question

以下变量是通过拉普拉斯变换得到的ODE系统的解。问题是，我如何将其评估为t？

的函数

zs =

(426453367703541750000*sin(t))/422998807223231216101 - (126885219268500000*cos(t))/422998807223231216101 - (143127622539985885236418500000*sum(exp(r3*t)/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101 - (898981813790513658018000000*sum((r3*exp(r3*t))/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101 - (35837444893658057322750000*sum((r3^2*exp(r3*t))/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101 + (10746289875507070500000*sum((r3^3*exp(r3*t))/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101


zu =

(423526351592241700000*sin(t))/422998807223231216101 - (119538342000000*cos(t))/422998807223231216101 - (21856954524657863661418500000*sum(exp(r3*t)/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101 - (935131412760109308018000000*sum((r3*exp(r3*t))/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101 - (35869453347570289778100000*sum((r3^2*exp(r3*t))/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101 + (10124060799006000000*sum((r3^3*exp(r3*t))/(2*(169386*r3^3 + 3312090*r3^2 + 336237395*r3 + 891000000)), r3 in RootOf(s3^4 + (736020*s3^3)/28231 + (336237395*s3^2)/84693 + (594000000*s3)/28231 + 13810500000/28231, s3)))/422998807223231216101

Answer 1

这些是用符号数学工具箱构建的吗？

尝试

t=0:0.01:10;
values_s = zs(t);
values_u = zu(t);

评估拉普拉斯的解决方案

1 个答案: