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.
For infinite summation, see Series (mathematics). For other uses, see Summation (disambiguation). In mathematics, summation (capital Greek sigma symbol: â) is the addition of a sequence of numbers; the result is their sum or total. If numbers are added sequentially from left to right, any intermediate result is a partial sum, prefix sum, or running total of the summation.