The following is the code for evaluating a definite integral of a given function by a Numerical Method called Trapezoidal Rule.
//Trapezoidal Rule //Evaluates the definite integral of a function f(x), from a to b. //Written By: Manas Sharma(www.bragitoff.com) funcprot(0); function ans=trapez(a, b, n, f)//function definition of simpson h=(b-a)/n; sum=0; for i=1:n-1 x=a+i*h; sum=sum+2*f(x); end ans=(h/2)*(f(a)+f(b)+sum); endfunction
You can either copy the code above and save it as a .sci file or download the file . Once you run the code, the function ‘trapez(a,b,n,f)’ can be called by other programs or even in the console.
a=initial limit(real no.)
b=final limit(real no.)
n=no. of sub-intervals(the higher the value of ‘n’ the better is the result.
The following code snippet evaluates the integral of 1/(1+x^2) from 0 to 2.