Question

    If X = 10°, find the value of: cos²(3X) +

    sin²(6X) - tan²(3X)
    A 7/6 Correct Answer Incorrect Answer
    B 5/6 Correct Answer Incorrect Answer
    C 11/12 Correct Answer Incorrect Answer
    D 1 Correct Answer Incorrect Answer

    Solution

    = cos²(30°) + sin²(60°) - tan²(30°)
    = (√3/2)² + (√3/2)² - (1/√3)²
    = 3/4 + 3/4 - 1/3 = 7/6

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