1/2{(a + b)² - (a - b)²} = ?
সমাধান
সঠিক উত্তর: Option A
(a + b)² = a² + 2ab + b²
(a - b)² = a² - 2ab + b²
1/2{(a + b)² - (a - b)²}
= 1/2{(a² + 2ab + b²) - (a² - 2ab + b²)}
= 1/2{a² + 2ab + b² - a² + 2ab - b²}
= 1/2{4ab}
= 2ab
(a - b)² = a² - 2ab + b²
1/2{(a + b)² - (a - b)²}
= 1/2{(a² + 2ab + b²) - (a² - 2ab + b²)}
= 1/2{a² + 2ab + b² - a² + 2ab - b²}
= 1/2{4ab}
= 2ab
