Cube root polar angle by three in order to define a cube root. With this definition, the principal cube root of a negative number is a complex number, and for instance will not be −2, but rather . This difficulty can also be solved by considering the cube root as a multivalued function: if we write the original complex number "x" in three equivalent forms, namely The principal complex cube roots of these three forms are then respectively Unless , these three complex numbers are distinct, even though the three representations of "x" were equivalent. For example, may then be calculated to
Dino Cube Dino Cube The Dino Cube is a cubic twisty puzzle in the style of the Rubik's Cube. It was invented in 1985 by Robert Webb, however it was not mass-produced until ten years later. It has a total of 12 external movable pieces to rearrange, compared to 20 movable pieces on the Rubik's Cube. Robert Webb designed and made the first prototype of what would become the Dino Cube in 1985; his original prototype was made entirely out of paper. Since then the puzzle was reinvented twice, but full mass production of the puzzle did not start until 1995. The