Algebraic Symbols

Question 1

≜

Answer 1

equal by definition

Question 2

≡

Answer 2

identical to

Question 3

⌊x⌋

Answer 3

floor brackets

floor brackets rounds number to lower integer

⌊4.3⌋= 4

Question 4

⌈x⌉

Answer 4

ceiling brackets

rounds number to upper integer

⌈4.3⌉= 5

Question 5

(a,b)

Answer 5

open interval

(a,b) = {x | a < x < b}

Question 6

[a,b]

Answer 6

closed interval

[a,b] = {x | a ≤ x ≤ b}

Question 7

∆

Answer 7

discriminant

could also be “delta”

Question 8

∑

Answer 8

Sigma Notation

Also known as Summation

Question 9

∑∑

Answer 9

Double Summation

Question 10

∏

Answer 10

Capital Pi

∏ xi=x1∙x2∙…∙xn

Question 11

∞

Answer 11

Lemniscate

Question 12

e

Answer 12

Euler’s Number

e = 2.718281828…

Question 13

γ

Answer 13

Euler-Mascheroni constant

constant γ = 0.5772156649…

Question 14

φ

Answer 14

Golden Ratio

approximately 1.618

Question 15

π

Answer 15

Pi Constant

π = 3.141592654…

Question 16

{ }

Answer 16

Set

in relation to “Set Theory”

Question 17

∀

Answer 17

“For All/Any”

∀ squares D, D is a rectangle

Question 18

∃

Answer 18

There exists

∃x∈N:x is even

Question 19

3√

Answer 19

Cube Root

We use the cube root symbol in the following way. ∛27 = 3

Question 20

4√

Answer 20

Fourth Root

The fourth root of 16 is 2, i.e. 2 × 2 × 2 × 2 = 16.

Question 21

〈x, y〉

Answer 21

Inner Product

Question 22

| A |

Answer 22

Determinant of Matrix A