Cube (algebra)

Cube (algebra)

In arithmetic and algebra, the cube of a number n is its third power — the result of the number multiplied by itself twice:

n3 = n × n × n.

This is also the volume formula for a geometric cube with sides of length n, giving rise to the name. The inverse operation of finding a number whose cube is n is called extracting the cube root of n. It determines the side of the cube of a given volume. It is also n raised to the one-third power.

The cube of a number or any other mathematical expression is denoted by a superscript 3, for example 23 = 8 or (x+1)3.

A perfect cube (also called a cube number, or sometimes just a cube) is a number which is the cube of an integer.

The positive perfect cubes up to 603 are (sequence A000578 in OEIS):

13 = 1 113 = 1331 213 = 9261 313 = 29791 413 = 68921 513 = 132651
23 = 8 123 = 1728 223 = 10648 323 = 32768 423 = 74088 523 = 140608
33 = 27 133 = 2197 233 = 12167 333 = 35937 433 = 79507 533 = 148877
43 = 64 143 = 2744 243 = 13824 343 = 39304 443 = 85184 543 = 157464
53 = 125 153 = 3375 253 = 15625 353 = 42875 453 = 91125 553 = 166375
63 = 216 163 = 4096 263 = 17576 363 = 46656 463 = 97336 563 = 175616
73 = 343 173 = 4913 273 = 19683 373 = 50653 473 = 103823 573 = 185193
83 = 512 183 = 5832 283 = 21952 383 = 54872 483 = 110592 583 = 195112
93 = 729 193 = 6859 293 = 24389 393 = 59319 493 = 117649 593 = 205379
103 = 1000 203 = 8000 303 = 27000 403 = 64000 503 = 125000 603 = 216000

Geometrically speaking, a positive number m is a perfect cube if and only if one can arrange m solid unit cubes into a larger, solid cube. For example, 27 small cubes can be arranged into one larger one with the appearance of a Rubik's Cube, since 3 × 3 × 3 = 27.

The pattern between every perfect cube from negative infinity to positive infinity is as follows,

n3 = (n − 1)3 + 3(n − 1)n + 1.

or

n3 = (n + 1)3 − 3(n + 1)n − 1.

Read more about Cube (algebra):  Cubes in Number Theory, History