quad_trapezoid, a MATLAB code which interactively applies a trapezoid quadrature rule using n intervals to estimate the integral of a function f(x) over an interval [a,b].
The user enters a formula for f(x), the values of a and b, and the value of n.
The program sets up the trapezoid rule, applies it to the integrand, and reports the integral estimate.
The program can be invoked by a function call, in which case the string specifying f(x) must be quoted:
q = quad_trapezoid ( 'x^2', -1, 3, 5 )
or, if called with no arguments, it will request them:
q = quad_trapezoid ( )
Enter function formula, like x^2: x^2
Enter left limit, a: -1
Enter right limit, b: 3
Enter number of interals: 5
The function is specified as a string which is either:
The string should not contain any spaces between symbols, except when it is passed as a function argument in quotes.
It is not necessary to use the "dot" notation for expressions involving '*', '/', or '^', but it doesn't hurt either.
Examples of function specifications:
x^2
x.^2
3/(x^4+5*x-6)
sin(7*x)*sqrt(x)/8
wiggle(x) <-- where "wiggle.m" is a user-provided M file.
The computer code and data files made available on this web page are distributed under the MIT license
quad_trapezoid is available in a MATLAB version.
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