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    Question

    If sin (a + b) = (√3/2) and cos (a – b) = (√3/2),

    then find sin a.
    A 1/2 Correct Answer Incorrect Answer
    B 1/√2 Correct Answer Incorrect Answer
    D 1 Correct Answer Incorrect Answer

    Solution

    Given: sin (a + b) = (√3/2) and cos (a – b) = (√3/2)

    So, sin (a + b) = sin 60 o

    Or, a + b = 60 o  ………. (I)

    And cos (a – b) = cos 30 o

    Or, (a – b) = 30 o  ……… (II)
    On adding equation (I) and (II), we have;

    2a = 90 o

    Or, a = 45 o

    So, required value = sin 45 o  = (1/√2)

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