Derivative after Numerical Integral
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hello everyone,
I have a function of x, however I get it after calculating a numerical integral, such as:
a = @(x) (integral(@(x1) sqrt((x+4).*(x1+2)./(x1+1)),0,1))
I need to take the derivative of a in terms of x, and then I calculate the values of diff(a) for different x values.
Any help will be appreciated.
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Star Strider
2019-5-27
编辑：Star Strider
2019-5-27
Try this:
dfdx = @(f,x) (f(x + 1E-8) - f(x)) ./ 1E-8; % Simple Numeric Derivative
a = @(x) (integral(@(x1) sqrt((x+4).*(x1+2)./(x1+1)),0,1, 'ArrayValued',1))
x = linspace(-1, 1, 25);
dadx = dfdx(a,x);
figure
plot(x, dadx)
grid
Make appropriate changes to ‘x’ for your needs.
EDIT —
You can also use the gradient (link) function to calculate the derivative of a (regularly-spaced) vector of values proeuced by your ‘a’ function.
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