Why I can't get the solution from integral function?

k= 0.2;              %thermal conductivity
lambda= 2.4048;      %eigenvalues
t=5;                 %time interval

fun1=@(t) exp(k.*lambda.^2.*t);
q1=integral(fun1,0,5);
C1=Amn.*exp(-k.*lambda.^2.*t);
Z=exp(-k.*lambda.^2.*t);
Tmn(t)=Z.*q1+C1

Command window

Undefined function or method 'integral' for input arguments of type 'function_handle'.
Error in ==> at 6
q1=integral(fun1,0,5);

Answer 1

[madhan ravi]

If you have an older version of matlab try using quad() released in 2006a but look into quadgk() as suggested by sir Walter.

see https://www.mathworks.com/help/matlab/ref/quad.html#bt5uonq-1_seealso

instead of integral() released in 2012a

see https://www.mathworks.com/help/matlab/ref/integral.html#btbbkta-1_seealso

My version is 2018b

I got the solution though:

>> k= 0.2;              %thermal conductivity
lambda= 2.4048;      %eigenvalues
t=5;                 %time interval
fun1=@(t) exp(k.*lambda.^2.*t);
q1=integral(fun1,0,5)

q1 =

  279.9143

>> 

[Walter Roberson]

quadgk was often better than quad. The best numeric integrater to use dependes in part on whether your boundaries were infinite .

[madhan ravi]

Thank you sir Walter but the release date is not mentioned in the doc

[Walter Roberson]

r2007b for quadgk

[madhan ravi]

Thank you sir Walter :)