MATLAB积分函数integral()的使用方法

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Abstract

This blog is to illustrate the usage of some definite functions, such as, integral() & int() in Matlab. The examples are given as follows.

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一、integral()

This function is only used to solve numeric functions.

Integrate f(x) = exp(-x.^2) from 0 to infinity:

 f = @(x) exp(-x.^2)
 Q = integral(f,0,Inf)

To use a parameter in the integrand:

f = @(x,c) 1./(x.^3-2*x-c)
Q = integral(@(x)f(x,5),0,2)

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二、int()

This function can be used to solve symbolic functions.

int(S,v,a,b) is the definite integral of S with respect to v from a to b. The integration interval can also be specified using a row or a column vector with two elements, i.e., valid calls are also int(S,v,[a,b]) or int(S,v,[a b]) and int(S,v,[a;b]).

% syms x y; % define signs
% f(x)=x*(3+(7*x+5)/(1+x)); % Define the integrand function
% value=int(f,x,1,2); % Solve the difinition integral from 1 to 2
% y=double(value); % Translate *value* from symbolic to numeric
% disp(k1);  
% disp(y);

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