如何在Matlab中计算此无限和? [英] how do I compute this infinite sum in matlab?

问题描述

对于给定的x和tau，我想在Matlab中计算以下无限和:

I want to compute the following infinite sum in Matlab, for a given x and tau:

在x = 0.5和tau = 1的情况下，我尝试了以下代码:

I tried the following code, given x=0.5 and tau=1:

symsum((8/pi/pi)*sin(n*pi*0.5)*sin(n*pi*0.5)*exp(-n*n*pi*pi)/n/n,1,inf)

但是我明白了:

(228155022448185*sum((exp(-pi^2*n^2)*((exp(-(pi*n*i)/2)*i)/2 - (exp((pi*n*i)/2)*i)/2)^2)/n^2, n == 1..Inf))/281474976710656

假设总和收敛，我想要一个明确的值.我究竟做错了什么?当返回符号求和结果时，Matlab似乎不计算exp().如何告诉Matlab计算指数值?

I want an explicit value, assuming the sum converges. What am I doing wrong? It seems like Matlab doesn't compute exp() when returning symsum results. How do I tell Matlab to compute evaluate the exponentials?

推荐答案

转换为两倍

double(symsum(...))

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