Beginning of Essay
is not regarded as having a direct role in fluid mechanics but is included because he is my son's favorite mathematician. was the first to represent mathematical quantities by letters and introduced the plus (+) and minus (-) symbols. He derived a formula for ....

Middle of Essay
.... Henry IV of France and deciphered the Spanish code in intercepted messages. Viète introduced the first systematic algebraic notation in his book In artem analyticam isagoge (1591). He demonstrated the value of symbols by using plus + and minus - signs for operations, and letters to represent unknowns. He suggested using letters as symbols for quantities, both known and unknown. He used vowels for the unknowns and consonants for known quantities. The convention where letters near the beginning of the alphabet represent known quantities while letters near the end represent unknown quantities was introduced later by Descartes in La Gèometrie . This c ....