Math Olympiad | A Nice Algebra Problem | VIJAY Maths

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  • Опубліковано 26 жов 2024

КОМЕНТАРІ • 4

  • @Rocio62154
    @Rocio62154 3 дні тому +2

    SENSATIONAL!

  • @key_board_x
    @key_board_x 4 дні тому +3

    (a + b)² = a² + 2ab + b² → given: a + b = 1
    1 = a² + 2ab + b² → given: a² + b² = 2
    1 = 2 + 2ab
    ab = - 1/2
    (a + b)⁴ = (a + b)².(a + b)²
    (a + b)⁴ = (a² + 2ab + b²).(a² + 2ab + b²)
    (a + b)⁴ = a⁴ + 2a³b + a²b² + 2a³b + 4a²b² + 2ab³ + a²b² + 2ab³ + b⁴
    (a + b)⁴ = a⁴ + b⁴ + 6a²b² + 4a³b + 4ab³
    (a + b)⁴ = a⁴ + b⁴ + 6a²b² + 4ab.(a² + b²) → given: a² + b² = 2
    (a + b)⁴ = a⁴ + b⁴ + 6a²b² + 8ab
    (a + b)⁴ = a⁴ + b⁴ + ab.(6ab + 8) → recall: ab = - 1/2
    (a + b)⁴ = a⁴ + b⁴ + (- 1/2).(- 3 + 8)
    (a + b)⁴ = a⁴ + b⁴ - (5/2) ← equation (1)
    a⁴ + b⁴ = (a + b)⁴ + (5/2) → given: a + b = 1
    a⁴ + b⁴ = 1 + (5/2)
    a⁴ + b⁴ = 7/2 ← equation (2)
    (a + b)⁸ = [(a + b)⁴]²
    (a + b)⁸ = [a⁴ + b⁴ - (5/2)]²
    (a + b)⁸ = a⁸ + a⁴b⁴ - (5/2).a⁴ + a⁴b⁴ + b⁸ - (5/2).b⁴ - (5/2).a⁴ - (5/2).b⁴ + (25/4)
    (a + b)⁸ = a⁸ + b⁸ + 2a⁴b⁴ - 5a⁴ - 5b⁴ + (25/4)
    (a + b)⁸ = a⁸ + b⁸ + 2a⁴b⁴ - 5.(a⁴ + b⁴) + (25/4) → recall: ab = - 1/2
    (a + b)⁸ = a⁸ + b⁸ + 2.(- 1/2)⁴ - 5.(a⁴ + b⁴) + (25/4)
    (a + b)⁸ = a⁸ + b⁸ - 5.(a⁴ + b⁴) + (51/8) → recall (2): a⁴ + b⁴ = 7/2
    (a + b)⁸ = a⁸ + b⁸ - (35/2) + (51/8)
    (a + b)⁸ = a⁸ + b⁸ - (89/8) ← equation (3)
    a⁸ + b⁸ = (a + b)⁸ + (89/8) → given: a + b = 1
    a⁸ + b⁸ = 1 + (89/8)
    a⁸ + b⁸ = 97/8 ← equation (4)
    (a + b)¹² = (a + b)⁸. (a + b)⁴ → recall (3)
    (a + b)¹² = [a⁸ + b⁸ - (89/8)].(a + b)⁴ → recall (1)
    (a + b)¹² = [a⁸ + b⁸ - (89/8)].[a⁴ + b⁴ - (5/2)]
    (a + b)¹² = a¹² + a⁸b⁴ - (5/2).a⁸ + a⁴b⁸ + b¹² - (5/2).b⁸ - (89/8).a⁴ - (89/8).b⁴ + (445/16)
    (a + b)¹² = a¹² + b¹² + a⁸b⁴ + a⁴b⁸ - (5/2).a⁸ - (5/2).b⁸ - (89/8).a⁴ - (89/8).b⁴ + (445/16)
    (a + b)¹² = a¹² + b¹² + a⁴b⁴.[a⁴ + b⁴] - (5/2).[a⁸ + b⁸] - (89/8).[a⁴ + b⁴] + (445/16)
    (a + b)¹² = a¹² + b¹² + [a⁴ + b⁴].[a⁴b⁴ - (89/8)] - (5/2).[a⁸ + b⁸] + (445/16) → recall (2): a⁴ + b⁴ = 7/2
    (a + b)¹² = a¹² + b¹² + [7/2].[a⁴b⁴ - (89/8)] - (5/2).[a⁸ + b⁸] + (445/16) → recall (4): a⁸ + b⁸ = 97/8
    (a + b)¹² = a¹² + b¹² + [7/2].[a⁴b⁴ - (89/8)] - (5/2).[97/8] + (445/16) → recall: ab = - 1/2
    (a + b)¹² = a¹² + b¹² + [7/2].[(- 1/2)⁴ - (89/8)] - (5/2).[97/8] + (445/16)
    (a + b)¹² = a¹² + b¹² + [7/2].[- (177/16)] - (485/16) + (445/16)
    (a + b)¹² = a¹² + b¹² - (1239/32) - (485/16) + (445/16)
    (a + b)¹² = a¹² + b¹² - (1319/32)
    a¹² + b¹² = (a + b)¹² + (1319/32) → given: a + b = 1
    a¹² + b¹² = 1¹² + (1319/32)
    a¹² + b¹² = 1351/32