Question

Care e formula ptr (a+b+c+d)^2?
Ms mult

Answer 1

$E~de~fapt~acelasi~lucru~cu~(x+y)^2. \\ \\ \Big ((a+b)+(c+d) \Big)^2=(a+b)^2+2(a+b)(c+d)+(c+d)^2. \\ \\ (a+b+c+d)^2=a^2+b^2+c^2+d^2+2ab+2ac+2ad+2bc+2bd+ \\ \\ +2cd.$