Question

Докажите тождество
2(a+b)^ -2 (a-b)^=8ab...

Answer 1

2(а+в)² - 2(а-в)² = 8ав,
2а² + 4ав + в² - 2а² + 4ав - в² = 8ав,
4ав + 4ав = 8ав,
8ав = 8ав

Answer 2

1) 2( a + b )^2 = 2 ( a^2 + 2ab + b^2 ) = 2a^2 + 4ab + 2b^2
2) - 2( a - b)^2 = - 2( a^2 - 2ab + b^2 ) = - 2a^2 + 4ab - 2b^2
3) 2a^2 + 4ab + 2b^2 - 2a^2 + 4ab - 2b^2 = 8ab
4) 8ab = 8ab