Integration2011. 6. 1. 11:32

The Trapezoidal Rule

It is the method of approximation a difinite integral with using trapezoids.
Assume that f is ontinuous and positive on the interval [a,b].
So, the definite integral f(x) a to b as x values represents the area of the region bounde by
the graph of f and the x-axis, from x=a to x=b.
By adding these trapezoids up, you can approximate integrations.

(1/2)*(b-a)*(f(x[0])+2*f(x[1])+2*f(x[2])+`...`+2*f(x[N-1])+f(x[N]))/N

Here are examples.



with(Student[Calculus1]);
>ApproximateInt(sin(x),x=0..π, method=trapezoid, output=plot)















As n, the number of subintervals, is going to infinity,
approximation of an integral approaches its real value.  



with(Student[Calculus1]);
>ApproximateInt(sin(x),x=0..π, method=trapezoid, output=animation)

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