1,75. Докажите равновесие: (a,b,c-векторы) 1)(a + b) {}^{2} + (a - b) {}^{2} = 2(a {}^{2} + b {}^{2})
2)(a + b) {}^{2} - (a - b) {}^{2} = 4ab
3)(a + b + c) {}^{2} = a {}^{2} \times b {}^{2} + c {}^{2} + 2a \times b + 2a \times c + 2b \times c

KaterinaFadeeva KaterinaFadeeva    3   17.10.2020 11:06    1