shoney 发表于 2011-6-15 05:41:35

解超越方程

超越方程来自一本参考书,书上给出了解,我自己试着用matlab解了下,得不到结果,达人帮忙看看,谢谢
超越方程见附件1我的语句见附件2

zccbest 发表于 2011-6-15 14:35:43

既然是超越方程当然是没有解释解了,不应该再用solve求解

qibbxxt 发表于 2011-6-15 16:51:34

clear;clc;close all
s = 0.121;
p = 0.126;
v = 2.87;
f = @(x) (s./(x.*sqrt(pi).*exp(x.^2).*erf(x)) + p./(v.*x.*sqrt(pi).*exp(v.*x.^2).*erfc(v.*x)) - 1);
figure(1)
fplot(f,[-0.5,-0.15]);
figure(2)
fplot(f,);
la = fsolve(f,[-0.2,0.2])
Equation solved.

fsolve completed because the vector of function values is near zero
as measured by the default value of the function tolerance, and
the problem appears regular as measured by the gradient.

<stopping criteria details>


la =

   -0.2352    0.2817

nwcwww 发表于 2011-6-15 21:37:54

clear;clc;close all
s = 0.121;
p = 0.126;
v = 2.87;
f = @(x) (s./(x.*sqrt(pi).*exp(x.^2).*erf(x)) + p./(v.*x.*sqrt(pi).*exp(v.*x.^2).*erfc(v.*x)) - 1);
figure(1)
fplot(f,[-0.5,-0.15]);
figure(2 ...
qibbxxt 发表于 2011-6-15 16:51 http://forum.simwe.com/images/common/back.gif

f里面有一个v^2被写成v了
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