Im using the integral2 function and getting an error as shown below. i tried all possible ways to solve it but again the same error is coming. Kindy provide me with an answer

Code:

clear;
clc;
L=90e-6;
B=4.5e-6;
H=2e-6;
alpha=2.51e-6;
C=711;
T0=300;
K=170;
rho=2300;
nu=0.2;
E=165.81e9;
G=E/(2*(1+nu));
% considering the entire length of the section
syms x y
N1=(1/(1*L*H))*(x-L)*(y-H);
N2=(1/(1*L*H))*(x)*(y-H);
N3=(1/(1*L*H))*(x)*(y);
N4=(1/(1*L*H))*(x-L)*(y);
N=[N1 N2 N3 N4];
f=(K*((diff(N,x,1)*diff(N',x,1))+(diff(N,y,1)*diff(N',y,1))));
fun1= @(x,y)(f);
Ke=integral2(fun1,0,L,0,H);

My error:

Error using integral2Calc>integral2t/tensor (line 231)
Input function must return 'double' or 'single' values. Found 'sym'.

Error in integral2Calc>integral2t (line 55)
[Qsub,esub] = tensor(thetaL,thetaR,phiB,phiT);

Error in integral2Calc (line 9)
    [q,errbnd] = integral2t(fun,xmin,xmax,ymin,ymax,optionstruct);

Error in integral2 (line 106)
    Q = integral2Calc(fun,xmin,xmax,yminfun,ymaxfun,opstruct);

Error in paulfem (line 23)
Ke=integral2(fun1,0,L,0,H);

Answer 1

[Walter Roberson]

fun1= matlabFunction(f,'vars', [x y]);

[Sandhya Pai]

Thank you very much for the quick response. My error was resolved.

Answer 2

[Steven Lord]

The integral2 function performs numeric integration. To integrate a symbolic expression with integral2 you would need to create a function handle from it using matlabFunction as Walter showed. Alternately call the int function twice to perform symbolic integration.

[Sandhya Pai]

Thank you very much for the quick response. My error was resolved.