(c - d)2 - (c + d)2
= (c^2 - 2cd + d^2) - (c^2 + 2cd + d^2)
= c^2 - 2cd + d^2 - c^2 - 2cd - d^2
= -4cd
Таким образом, (c - d)2 - (c + d)2 = -4cd.
(c - d)2 - (c + d)2
= (c^2 - 2cd + d^2) - (c^2 + 2cd + d^2)
= c^2 - 2cd + d^2 - c^2 - 2cd - d^2
= -4cd
Таким образом, (c - d)2 - (c + d)2 = -4cd.