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我把我那个级数重新整理了一下,然后用matlab求了一下和,结果如下:>> syms y k n t
>> s=1/k*sin(n*pi*1e-9)*exp((-y*sqrt(5.1*n*k*1e-9/k))*cos((5.1*n*k*1e-9/k)+2*pi*n*t*1e-9/k);
>> s=1/k*sin(n*pi*1e-9)*exp(-y*sqrt(5.1*n*k*1e-9/k))*cos((5.1*n*k*1e-9/k)+2*pi*n*t*1e-9/k);
>> b1=symsum(s,1,inf)
b1 =
piecewise([exp((51/10000000000*n)^(1/2)) <> 1 and 0 < Re(sign(n)^(1/2)), -(cos((51*n)/10000000000 + (pi*n*t)/(500000000*k))*sin((pi*n)/1000000000))/(k*exp(((51*n)/10000000000)^(1/2))*(1/exp(((51*n)/10000000000)^(1/2)) - 1))], [exp((51/10000000000*n)^(1/2)) <> 1 and Re(sign(n)^(1/2)) < 0, -(cos((51*n)/10000000000 + (pi*n*t)/(500000000*k))*sin((pi*n)/1000000000)*(1/(exp(((51*n)/10000000000)^(1/2))*(1/exp(((51*n)/10000000000)^(1/2)) - 1)) - limit(exp(-y*(51/10000000000*n)^(1/2))/(exp(-(51/10000000000*n)^(1/2)) - 1), y = Inf)))/k])
唉。。。 |
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