HP 48gII Definite integrals, ∫ab f (x)dx = F(b) − F(a)

Please notice that functions SIGMAVX and SIGMA are designed for integrands that involve some sort of integer function like the factorial (!) function shown above. Their result is the so-called discrete derivative, i.e., one defined for integer numbers only.

Definite integrals

In a definite integral of a function, the resulting anti-derivative is evaluated at the upper and lower limit of an interval (a,b) and the evaluated values subtracted. Symbolically, we write

∫ab f (x)dx = F(b) − F(a),

where f(x) = dF/dx.

To calculate definite integrals of functions using the CAS variable VX (typically, ‘X’), use function PREVAL(f(x),a,b). For example,

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