Integrate multivariate fuction with respect to one variable and pass the result to another function for integration.

Hi.. I a trying to evaluate the integral in matlab but not able to getting error in matlab. code is given below:

fun= @(x, y) x.*exp(-y.*x);
c= @(y)integral(@(x) fun, 0,1);
fun1= @(y) 1/2-(1/pi).*y.*c;
c1 = integral(fun1, 0,1);

Could any one can help me regard this. Any suggestions will be appreciated. Thanks in advance.

Answer 1

[Walter Roberson]

Notice you have:

fun= @(x, y) x.*exp(-y.*x);

which is a function of two variables. But you try

c= @(y)integral(@(x) fun, 0,1);

which does not pass any parameters to the function. You probably intended

c= @(y)integral(@(x) fun(x), 0,1);

But notice that you are not passing y, so you would need

c= @(y) integral(@(x) fun(x, y), 0,1);

Then you have

fun1= @(y) 1/2-(1/pi).*y.*c;
c1 = integral(fun1, 0,1);

this attempts to invoke c, but c is a function handle. You have to pass a value to the handle:

fun1 = @(y) 1/2-(1/pi).*y.*c(y);

c1 = integral(fun1, 0,1);

I think that should work.

[Shweta Rajoria]

Thank you for the answer Walter and KSSV i hope this will help me.

Answer 2

[KSSV]

You have to provide the value of c. Check the below code for c = 1 ;

fun= @(x, y) x.*exp(-y.*x);
c= @(y)integral(@(x) fun, 0,1);
% fun1= @(y) 1/2-(1/pi).*y.*c;
fun1= @(y) 1/2-(1/pi)*y;
c1 = integral(fun1, 0,1);