We shall begin by writing x0 , x1, cos0 x, cos1 x, above the columns V0, V1, V2, V3; then since, from the form of the two functions to be combined, the terms which are to compose the products will be of the following nature, x0·cos0 x, x0·cos1 x, x1·cos0 x, x1·cos1 x, these will be inscribed above the columns V4, V5, V6, V7.