MATLAB: Solving an integral with variable as upper limit and plotting the solution

integral with varying upper limit

How can I solve an integral when the upper limit is a variable, and then plot the solution? My integral is as follows: Integral of e^(-(y^2))dy and my upper limit is x, while the lower limit is negative infinity. X and y are variables. I have tried using the trapz function, but then you must have a constant as upper limit. I have also tried using the int-funtion, but that is only solving for an indefinite integral. Does anyone know what I should do?

Best Answer

Your function is equal to

sqrt(pi)/2*(1+erf(x))

Best wishes

Torsten.

Related Solutions

MATLAB: I have the error message : Subscript indices must either be real positive integers or logicals.

its pretty simple. In your testprogramm you saved erf(x1) in erf1. in your programm you overwrite erf:

erf=erf(x)

so that erf is no longer a function (handle)

change that line to

erf1=erf(x)
% or
erf0=erf(x)

and your problem should be solved

MATLAB: ‘I get error saying Input function must return ‘double’ or ‘single’ values. Found ‘sym’.’ because max is defined in symbolic variable, how to overcome this issue?

Your ymax function returns a sym result. If you specify the limits as function handles in your call to integral2 those function handles must return a numeric result, not a symbolic result.

If you want to integrate with a symbolic limit, work solely with symbolic variables and call the int function twice instead of calling integral2.

If you want to be able to specify b when you call integral2 rather than when you define the ymax function:

ymax = @(x, b) b.*sqrt(x);

Now when you call integral2 (I'm assuming you've defined fun, xmin, xmax, and ymin before this call) specify b:

% Use b = 1
Q = integral2(fun, xmin, xmax, ymin, @(x) ymax(x, 1));
% Use b = x.^2
Q = integral2(fun, xmin, xmax, ymin, @(x) ymax(x, x.^2));

Best Answer

Related Solutions

MATLAB: I have the error message : Subscript indices must either be real positive integers or logicals.

MATLAB: ‘I get error saying Input function must return ‘double’ or ‘single’ values. Found ‘sym’.’ because max is defined in symbolic variable, how to overcome this issue?

Related Question