Free Graphing Calculator
A powerful, flexible graphing calculator
Does far more than most calculators out there.
1) Scientific Calculator. Simple to grasp and easy to use, but powerful features are available when you need them. Available functions include the following:
• the usual arithmetic functions and exponentiation.
• square root, cube root, nth root, natural log, log base 10, log of arbitrary base, absolute value, factorial, permutations (nPr), combinations (nCr), modulus, random integer, ...