I get the error "Undefined function 'symsum' for input arguments of type 'double'. while solving the equation given below.Please help me.

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PARVEEN KUMAR SINGHAL 2020-2-23

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/507035-i-get-the-error-undefined-function-symsum-for-input-arguments-of-type-double-while-solving-th

评论： PARVEEN KUMAR SINGHAL 2020-2-25

clc
clear all
syms m x k 
m=5;
k=2;
alpha=2;
beta=(1.65)*(10^(-5));
sai=10;
rho=15;
pt=2;
pn=16.56*10^(-14);
g = @(x)symsum((((1/factorial(k))*(m*sai*pn/2*beta)^k)),k,0,m-1).*exp(-(rho.*x)+((m*sai*pn*x.^alpha)/(beta*pt)))*x.^(alpha*1);
format long
f= rho*integral(g,0,inf)
plot(alpha,f,'*')

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Walter Roberson 2020-2-23

在 MATLAB Online 中打开

In particular you had

syms k
k=2

But the second line removes the identity of k as a symbolic variable

PARVEEN KUMAR SINGHAL 2020-2-25

Thankyou Very Much Sir. Really it solved my problem.

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采纳的回答

Cameron B 2020-2-23

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/507035-i-get-the-error-undefined-function-symsum-for-input-arguments-of-type-double-while-solving-th#answer_416919

编辑：Cameron B 2020-2-23

在 MATLAB Online 中打开

I ran the script below and got a very large answer. You should check my code/output as there may be a mistake (using matlab mobile and don’t have time to check it), but at least there’s no error.

    clc
clear all
syms k x
m=5;
alpha=2;
beta=(1.65)*(10^(-5));
sai=10;
rho=15;
pt=2;
pn=16.56*10^(-14);
c=(m*sai*pn)/(beta*pt);
fun=exp(-1.*(rho.*x + c.*x.^alpha)).*x.^(alpha*k);
g = symsum(1/factorial(k).*c.^k.*rho.*int(fun,0,inf),k,0,m-1);
g=double(g);