Question

    If sin(A + B) = sinAcosB + cosAsinB, then the value of

    sin75° is
    A (√3 + 1)/√2 Correct Answer Incorrect Answer
    B (√2 + 1)/2√2 Correct Answer Incorrect Answer
    C (√3 + 1)/2√2 Correct Answer Incorrect Answer
    D (√3 + 1)/2 Correct Answer Incorrect Answer

    Solution

    Since, sin(A + B) = sinAcosB + cosAsinB
    Let A = 30 o  and B = 45 o
    sin(30 o  + 45 o ) = sin30 o cos45 o  + cos30 o sin45 o  = 1/2√2 + √3/2√2 = (√3 + 1)/2√2

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