Math Symbol Meanings???

Question

what do
!
∑
┴
and
(a,b)
mean? sorry its just back to school and hard to remember

what is a real number? i need ez definitions
rational number
irrational number
i missed a week of school =[

Answer 1

! = factorial
Example:
4! = 4 * 3 * 2 * 1 = 24

∑ = Greek letter sigma OR summation (ie "the sum of")
Example of summation:
∑(from i=1 to 3) of i = 1 + 2 + 3 = 6

┴ = perpendicular
Example:
f┴g ---> f is perpendicular to g

(a,b) = the coordinates a and b OR the open interval from a to b
Example of coordinates:
(1, 2) so the x-coordinate is 1 and y-coordinate is 2 when you plot the point (1, 2)
Example of intervals:
(1, 10) means "the open interval from 1 to 10"


edit:
real number: the union of all the irrationals and rationals; basically, any number that is not complex
rational: a number that can be put into the form p/q where p and q are both integers
irrational: a number that is not rational; that is, it cannot be put into the form p/q, p,q integers

Answer 2

Don't feel bad about not remembering. I've recently completed Honours in maths and I still look up some symbols.

! after an integer means the factorial (product of all integers from 1 to that number)
7! = 1*2*3*4*5*6*7

In logic probles, it could mean "unique", as in "there exist a unique element" that meets a given condition.

∑ is a capital letter S in the Greek alphabet. It is used for discrete sums. It will normally have a letter (identifying a variable) at the bottom, along with the starting value (e.g., n = 0) and a value at the top for the ending value (let us say, for this example, 10.
∑ will be followed by some expression containing the variable.

It means (in my example): the sum of all term, with n taking successive values from 0 to 10.

If the expression is (for example) 2^n, then the sum is:
2^0 + 2^1 + 2^2 + ... + 2^10.

┴ In geometry, this means perpendicular.

(a, b) could be a 2-D coordinate (as on a graph)

(x,y) = (3, 7)
The point corresponding to x=3 and y=7

could be an open interval:
x belongs to (3, 7) means x can take on any value between 3 and 7, but not exactly 3 nor exactly 7.

x belongs to [3, 7) is the same, except that x=3 is allowed, but not x=7.

In cyclic calculation, this could be a doublet or a swap (swap the third element for the seventh and vice-versa).

Believe me, if you go deep enough in maths, you will have to look them up as the same symbol could mean something different, depending what you are doing.

Answer 3

!, the exclamation point, represents the factorial. The factorial of an integer is the product of that integer with each of the integers small than it, down to 1. For example, 5! = 5*4*3*2*1 = 120.

∑ is the symbol for summation. Normally, it will identify an index and its lower bound under the symbol, the upper bound of the index above the symbol, and an expression using the index after the symbol. For example,

3
∑ n^2
n = 1

would mean "the summation for n equal to one through three of n squared," and it would be equal to 1^2 + 2^2 + 3^2 = 1 + 4 + 9 = 14.

┴ means perpendicular. For example, AB ┴ CD means that line AB is perpendicular to CD.

(a, b) could be an ordered pair. Unless you are told otherwise, a would be the x-coordinate and b would be the y-coordinate. It could also be the interval from a to b that does not include the endpoints a and b. [a, b] would be the interval that does include the endpoints.

Answer 4

! usually means factorial. So 6! would be the result of 6*5*4*3*2*1, and likewise for other numbers.

∑ usually means sum. So the result is the sum of anything following this, which in a lot of cases will be variables.

┴ usually stands for perpendicular. It would represent two lines that are perpendicular to each other.

(a,b) can mean many things. In relation to the perpendicular symbol though, if these are in the same context, it could represent a point on a line. So a point at coordinates (a,b) would be a units on the x-axis and b units on the y-axis. It could also represent other things though. Context would be the key.

Answer 5

!, in mathematics, is the factorial of a non-negative integer n is the product of all positive integers less than or equal to n.
Web: http://en.wikipedia.org/wiki/Factorial

∑,in mathematics, is a series is often represented as the sum of a sequence of terms. That is, a series is represented as a list of numbers with addition operations between them, for example this arithmetic sequence:
Web: http://en.wikipedia.org/wiki/%E2%88%91

┴ is called BOX DRAWING CHARACTERS.
Box drawing characters, also known as line drawing characters, or pseudographics, are widely used in text user interfaces to draw various frames and boxes. In graphical user interfaces these characters are useless, because it is much simpler to draw lines and rectangles directly with graphical APIs; besides, box drawing characters work only with fixed-width (monospaced) fonts.
Web: http://en.wikipedia.org/wiki/%E2%94%B4

(a,b) means a position of a point in the plane-rectangular coordinate system.

Answer 6

i think of it might help in case you gave some particular symbols which you mandatory help with. in case you have a textbook with their names or something you are able to try looking them up in case you haven't any longer already tried that.

Answer 7

! factorial
∑ sum
┴ perpendicular
and
(a,b) order pair (point in 2D)