One meaning of forceful is all about physical strength: The forceful throw carried the football past the goalposts. Another way to be forceful is to be emphatic or vehement: The child's forceful refusal to go to bed could not be ignored by the sleepy babysitter. Forceful literally means full of force, and force comes from the Latin fortis, strong, firm, or steadfast.
In addition to being the 18th letter of the Greek alphabet, sigma also means 'sum' and 'deviation' in the mathematics world. Learn what each symbol looks like and how each formula works. High School Precalculus: Homework Help Resource / Math Courses.
Haskell Curry defined mathematics simply as the science of formal systems. A formal system is a set of symbols, or tokens, and some rules telling how the tokens may be combined into formulas. In formal systems, the word axiom has a special meaning, different from the ordinary meaning of a self-evident truth.