error while using solve function with integral

3 次查看（过去 30 天）
modem sudhakar
modem sudhakar 2016-4-2
评论： Walter Roberson 2016-4-11
Please suggest the solution for the encoutering problem below:
syms x V; Pr=solve( int(x.^2.* exp(-x-1./(x+V)),x,1,inf )-0.5 ==0,V);

请先登录，再回答此问题。

回答（1 个）

Walter Roberson
Walter Roberson 2016-4-2
That equation has no real-valued solution. Are you expecting a complex-valued solution?
  5 个评论
显示 3更早的评论
modem sudhakar
modem sudhakar 2016-4-11
编辑：modem sudhakar 2016-4-11
Dear walter, I plotted the function by varying V as:
for V=0:1:10 plot(V,integral(@(x) x.^2.* exp(-x-1./(x+V)),1,inf )); hold on end
From this I can see that it is giving positive values. So, if I want get value of V for given integral value as:
solve(integral(@(x) x.^2.* exp(-x-1./(x+V)),1,inf ))==1.4,V)
From above 'for' loop the value should come as V=1. But it is giving the error as:
Undefined function or variable 'V'.
Error in @(x)x.^2.*exp(-x-1./(x+V))
Error in integralCalc/iterateScalarValued (line 314) fx = FUN(t);
Error in integralCalc/vadapt (line 133) [q,errbnd] = iterateScalarValued(u,tinterval,pathlen);
Walter Roberson
Walter Roberson 2016-4-11
You need to make the integral symbolic. Then vpasolve for V

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Utilities for the Solver 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by