Solve integral with a power

Question

Sylvain 2014-3-6

0
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https://ww2.mathworks.cn/matlabcentral/answers/120480-solve-integral-with-a-power

回答： Sylvain 2014-3-6

采纳的回答： Roger Stafford

Hi,

I try to solve the integral of an exponential function. Here is my code :

a1 = -0.0024 ; a0 = 0.0581 ;

fun1 = @(s,a,b) exp(a*s + (1/2)*b*(s^2)) ; fun2 = @(s) fun1(s,a0,a1) ; z = integral(fun2,10,45) ;

Matlab says : _____ Error using ^ Inputs must be a scalar and a square matrix. To compute elementwise POWER, use POWER (.^) instead. _____

If I use .^ there is no more problem, but I don't understand why s is not considered as a scalar. Does someone have some clue ?

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Answer 1

Roger Stafford 2014-3-6

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https://ww2.mathworks.cn/matlabcentral/answers/120480-solve-integral-with-a-power#answer_127338

在 MATLAB Online 中打开

The quadrature routine 'integral', in the process of computing an integral, will call on its given integrand function with vectors of values of the variable of integration. For that reason, the integrand function must be written so as to be able to accept vector inputs rather than one scalar at a time. Therefore you need ".^" as your power operator. The documentation at:

http://www.mathworks.com/help/matlab/ref/integral.html

states that "Integrand, specified as a function handle, defines the function to be integrated from xmin to xmax. For scalar-valued problems, the function y = fun(x) must accept a vector argument, x, and return a vector result, y."