Calculate the Product

Calculator for the multiplication with the product symbol Pi, Π. The product is a repeated multiplication with a start value m and an end value n. As running variable, which is increased by 1 in each step, i is used. Only this variable may occur in the product term. The basic arithmetic operations + - * / are allowed, as well as the power function, like pow(2#i) for 2ⁱ. Further allowed functions are sin(), cos(), tan(), asin(), acos(), atan(), log() for the natural logarithm and fac() for the factorial. Also, the constants e and pi can be used.

Example: with m=1 and n=10, Π i = 1*2*3*4*5*6*7*8*9*10 = 3628800 = 10! (factorial function)