Online Math Dictionary: S
Easy to understand math definitions for KAlgebra mathematics
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Scientific Notation Scientific notation is a way to write a number as the product of a number between 1 and 10 and a multiple of 10. Examples: 
Secant From trigonometry, the secant of an angle (in the picture below) is the ratio of the hypotenuse to the adjacent side: For more trig info, check out my reference sections on The Trigonometry of Circles and The Trigonometry of Triangles. 


Segment  Line Segment A line segment is the finite piece of line that connects two points in space. 



Semiannual A term often used in Algebra money problems, semiannually means twice a year. For information on how to solve compound interest problems, check out my lessons on Exponentials and Logarithms. 

Sequence A sequence is a list of numbers that typically changes according to some sort of pattern. A finite sequence example: 1, 3, 5, 7, 9 An infinite sequence example: 1, 4, 9, 16, 25, ... For more info on sequences, check out my lessons on Sequences & Series. 

Series A series is the sum of a sequence. Example: 1 + 3 + 5 + 7 + 9 = 25 For more info on sequences, check out my lessons on Sequences & Series. 

Set A set is a group of objects: 

Similar Triangles Similar triangles are triangles whose corresponding angles are congruent and whose sides are proportional (see the equivalent fractions to the right). 

Sine From trigonometry, the sine of an angle (in the picture below) is the ratio of the opposite side to the hypotenuse: For more trig info, check out my reference sections on The Trigonometry of Circles and The Trigonometry of Triangles. 











Square Numbers A square number is the answer when you take an integer and multiply it to itself: Here's a partial list of square numbers: 0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, ... 

Square Root Here is how we write a square root... It's made up of a radical sign and something inside called the radicand. The square root of a number (the radicand) is a number that produces the radicand when it is squared. Example: To learn more about radicals, check out my Radicals Review lesson. 

Subset A subset is a set whose members are part of a bigger set. Example: The set B is a smaller set whose members are part of the bigger set A: Here's how we write it... The "U" lying on its side is the symbol for "is a subset of." So, this says that the set B is a subset of the set A. 

Subtrahend When you do a subtraction problem, the subtrahend is the number you are taking off: 8  5 = 3 For more info, check out my Subtraction Lessons. 

Sum In an addition problem like 2 + 3 = 5, the sum is the answer. For more info, check out my Addition Lessons. 

Summation A summation is a fancy notation to represent a series (a list of things that you want to add together.) Here's an example: The complete description is pretty long... If you want more than this, check out my Summations Algebra Lesson on Sigma Notation. 







System of Equations A system of equations is when you have more than one equation AND more than one variable to solve for (the unknowns). Example: 2x  5y = 22 7x + 3y = 5 For information on how to solve systems of equations, check out my Systems of Equations Lessons for 2x2's and mySystems of Equation Lessons for 3x3's. 
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N  O  P  Q  R  S  T  U  V  W  no X's 
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