607
OF ENGINEERING FORMULÆ.
Algebraic Signs in obdinary use.
Plus, addition, 4. positive, compression. — Minus, tension, — negative, — subtraction. z= Equal to. Unequal to. Greater than. ^j> Not greater than. Less than. Not less. X Multiplied by. I ; Multiplied by. ; I (Is to (ratio). ; 1As; so is (ratio). : Divided by. _L Perpendicular to. II Parallel to. K Not parallel. ’. • Because. .'. Therefore. / Angle. □ Right angle. A Triangle. i 1 Parallelogram. □ Square. O Circumference. o Circle. Semicircle. D Quadrant. co Infinity. Arc, /«w Difference. ()[]{}— the numbers are to Example.— 5 («-ft); or 5[a-&]; o a : b :: c : d — a is t< a + b . ^(a + C — (1 a', a", a"1-, or V, quantities of the same 45° = 45 degrees; 25" = 25 seconds; 12" The first letters of tl are often used to deii whilst the last, as, y, quantities. The folio quently used as follows c Constant. d Differential (see Calculus). E Modulus of elas- ticity. / Integration (see Calculus). F or / Functions. g Gravity = 32’2. k Coefficient. M Modulus. n Any number. R° Radius in degrees of arc = 51° -2958. R' Do. minutes = 3437''75. V Square root. 8/Cabe root. £/Root of any No. n. Sin. a = the sine of a. Sin.-i a = the arc whose sine is a. (Sin. a)”1 = . k ' sm.a Vincula denoting that be taken together. r 5 a—b ; — 5 a — 5 b. b as c is to d. j)4-(c-d). biu, accents denoting dnd. 20' = 20 minutes; = 12 thirds. e alphabet, a, b, c, &c., ■>te known quantities, , to denote unknown wing letters are fre- u An angle. 5 Variation. A Finite difference. e Base of hyperbolic logarithms. Any angles. A Latitude. ir Ratio of circum- ference to diameter = 3-14159. p Radius. 2 Sum of finite quantities. a2 = a squared. a3 • a cubed. an — a raised to the power of a number equal n. a3 = «2,