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我编写了一个代码来评估蠕动泵中流速的临界值

dp = -(((theta - 1)+(1 + phi.*cos(2.*pi.*x))).*M.^3.*(cosh((1 + phi.*cos(2.*pi.*x)).*M)+ M.*beta.*sinh((1 + phi.*cos(2.*pi.*x)).*M)))./((1 + phi.*cos(2.*pi.*x)).*M.*cosh((1 + phi.*cos(2.*pi.*x)).*M)+(-1 +(1 + phi.*cos(2.*pi.*x)).*M.^2.*beta).*sinh((1 + phi.*cos(2.*pi.*x)).*M))-(alpha.*(M.^2.*((theta - 1)+(1 + phi.*cos(2.*pi.*x))).*(-1+2.*(1 + phi.*cos(2.*pi.*x)).^2.*M.^2+ cosh(2.*(1 + phi.*cos(2.*pi.*x)).*M)-2.*(1 + phi.*cos(2.*pi.*x)).*M.*sinh(2.*(1 + phi.*cos(2.*pi.*x)).*M)))./(8.*((1 + phi.*cos(2.*pi.*x)).*M.*cosh((1 + phi.*cos(2.*pi.*x)).*M)+(-1+(1 + phi.*cos(2.*pi.*x)).*M.^2.*beta).*sinh((1 + phi.*cos(2.*pi.*x)).*M)).^2));

和p = int(y,x,0,1 + phi.*cos(2.*pi.*x));

如果在 theta p = 0 的临界值，theta 的临界值是多少；我写了代码：

M = 2;
alpha = 0.2;
beta = 0.03;
phi = 0.6;
theta = 0;
x = 0.5;
y = -(((theta - 1)+(1 + phi.*cos(2.*pi.*x))).*M.^3.*(cosh((1 + phi.*cos(2.*pi.*x)).*M)+ M.*beta.*sinh((1 + phi.*cos(2.*pi.*x)).*M)))./((1 + phi.*cos(2.*pi.*x)).*M.*cosh((1 + phi.*cos(2.*pi.*x)).*M)+(-1 +(1 + phi.*cos(2.*pi.*x)).*M.^2.*beta).*sinh((1 + phi.*cos(2.*pi.*x)).*M))-(alpha.*(M.^2.*((theta - 1)+(1 + phi.*cos(2.*pi.*x))).*(-1+2.*(1 + phi.*cos(2.*pi.*x)).^2.*M.^2+ cosh(2.*(1 + phi.*cos(2.*pi.*x)).*M)-2.*(1 + phi.*cos(2.*pi.*x)).*M.*sinh(2.*(1 + phi.*cos(2.*pi.*x)).*M)))./(8.*((1 + phi.*cos(2.*pi.*x)).*M.*cosh((1 + phi.*cos(2.*pi.*x)).*M)+(-1+(1 + phi.*cos(2.*pi.*x)).*M.^2.*beta).*sinh((1 + phi.*cos(2.*pi.*x)).*M)).^2));
p = int(y,x,0,1 + phi.*cos(2.*pi.*x));
sym theta
solve( 'p','theta' );

检查一点，但我得到

Undefined function or method 'int' for input arguments of type 'double'.

你能帮我吗？谢谢。

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1 回答 1

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If what you are trying to do is Symbolic Integration, you need Symbolic Toolbox that INT function belong to. The variables should be symbolic (defined with sym or syms). Check the function syntax with examples in the documentation.

于 2012-04-08T04:36:06.283 回答