Sum of squares:1+2+3+...+n = n (n+1) (2n+1)/6.

Cubic difference: a 3-b 3 = (a-b) * (a 2+ab+b 2)

Cubic sum: a 3+b 3 = (a+b) (a 2-ab+b 2)

Cubic difference formula is also one of the commonly used formulas in mathematics, which is in contact with high school mathematics and occupies a very important position in mathematical research, even in advanced mathematics and calculus. Cubic difference formula and cubic sum formula * * * are called complete cubic formula.

Specifically: the sum of squares of two numbers plus the product of two numbers and then multiplied by the difference of two numbers, the product is equal to the cubic difference of two numbers.