Упростите выражение (a^1/4+b^1/4)^2-(a^1/4-b^1/4)^2

Лебедев Дмитрий Сергеевич

Учитель математики

Проверено учителем

Для упрощения данного выражения воспользуемся формулами сокращенного умножения. Выражение: (a1/4+b1/4)2(a1/4b1/4)2open paren a raised to the 1 / 4 power plus b raised to the 1 / 4 power close paren squared minus open paren a raised to the 1 / 4 power minus b raised to the 1 / 4 power close paren squared Способ 1: Использование формулы разности квадратов Формула разности квадратов: x2y2=(xy)(x+y)x squared minus y squared equals open paren x minus y close paren open paren x plus y close paren. В нашем случае: x=a1/4+b1/4x equals a raised to the 1 / 4 power plus b raised to the 1 / 4 power y=a1/4b1/4y equals a raised to the 1 / 4 power minus b raised to the 1 / 4 power Применим формулу:

  1. Вычислим разность (xy)open paren x minus y close paren:
    (a1/4+b1/4)(a1/4b1/4)=a1/4+b1/4a1/4+b1/4=2b1/4open paren a raised to the 1 / 4 power plus b raised to the 1 / 4 power close paren minus open paren a raised to the 1 / 4 power minus b raised to the 1 / 4 power close paren equals a raised to the 1 / 4 power plus b raised to the 1 / 4 power minus a raised to the 1 / 4 power plus b raised to the 1 / 4 power equals 2 b raised to the 1 / 4 power Вычислим сумму (x+y)open paren x plus y close paren:
    (a1/4+b1/4)+(a1/4b1/4)=a1/4+b1/4+a1/4b1/4=2a1/4open paren a raised to the 1 / 4 power plus b raised to the 1 / 4 power close paren plus open paren a raised to the 1 / 4 power minus b raised to the 1 / 4 power close paren equals a raised to the 1 / 4 power plus b raised to the 1 / 4 power plus a raised to the 1 / 4 power minus b raised to the 1 / 4 power equals 2 a raised to the 1 / 4 power Перемножим полученные результаты:
    2b1/42a1/4=4a1/4b1/42 b raised to the 1 / 4 power center dot 2 a raised to the 1 / 4 power equals 4 a raised to the 1 / 4 power b raised to the 1 / 4 power

Способ 2: Раскрытие квадратов суммы и разности Используем формулы (x+y)2=x2+2xy+y2open paren x plus y close paren squared equals x squared plus 2 x y plus y squared и (xy)2=x22xy+y2open paren x minus y close paren squared equals x squared minus 2 x y plus y squared.

  1. Раскроем первую скобку:
    (a1/4+b1/4)2=(a1/4)2+2a1/4b1/4+(b1/4)2=a1/2+2a1/4b1/4+b1/2open paren a raised to the 1 / 4 power plus b raised to the 1 / 4 power close paren squared equals open paren a raised to the 1 / 4 power close paren squared plus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus open paren b raised to the 1 / 4 power close paren squared equals a raised to the 1 / 2 power plus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus b raised to the 1 / 2 power Раскроем вторую скобку:
    (a1/4b1/4)2=(a1/4)22a1/4b1/4+(b1/4)2=a1/22a1/4b1/4+b1/2open paren a raised to the 1 / 4 power minus b raised to the 1 / 4 power close paren squared equals open paren a raised to the 1 / 4 power close paren squared minus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus open paren b raised to the 1 / 4 power close paren squared equals a raised to the 1 / 2 power minus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus b raised to the 1 / 2 power Вычтем второе выражение из первого:
    (a1/2+2a1/4b1/4+b1/2)(a1/22a1/4b1/4+b1/2)open paren a raised to the 1 / 2 power plus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus b raised to the 1 / 2 power close paren minus open paren a raised to the 1 / 2 power minus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus b raised to the 1 / 2 power close paren
    =a1/2+2a1/4b1/4+b1/2a1/2+2a1/4b1/4b1/2equals a raised to the 1 / 2 power plus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power plus b raised to the 1 / 2 power minus a raised to the 1 / 2 power plus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power minus b raised to the 1 / 2 power Приведем подобные слагаемые:
    a1/2a1/2=0a raised to the 1 / 2 power minus a raised to the 1 / 2 power equals 0
    b1/2b1/2=0b raised to the 1 / 2 power minus b raised to the 1 / 2 power equals 0
    2a1/4b1/4+2a1/4b1/4=4a1/4b1/42 a raised to the 1 / 4 power b raised to the 1 / 4 power plus 2 a raised to the 1 / 4 power b raised to the 1 / 4 power equals 4 a raised to the 1 / 4 power b raised to the 1 / 4 power

Ответ: 4a1/4b1/44 a raised to the 1 / 4 power b raised to the 1 / 4 power (или 4ab44 the fourth root of a b end-root ) Укажите, требуется ли перевести итоговый результат в формат радикалов (корней) или оставить в виде степеней.

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