New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    Determine the value of:(sin 38 o cos 52

    o  + cos 2  38 o ) X sin 30 o  + (cos 60 o tan 45 o ) X sec 60 o
    A 2 Correct Answer Incorrect Answer
    B 1/2 Correct Answer Incorrect Answer
    C 3/2 Correct Answer Incorrect Answer
    D 5/2 Correct Answer Incorrect Answer

    Solution

    (sin 38 o cos 52 o  + cos 2  38 o ) X sin 30 o  + (cos 60 o tan 45 o ) X sec 60 o

    = {sin 38 o cos (90 - 38 o ) + cos 2  38 o } X sin 30 o  + cos 60 o tan 45 o sec 60 o

    Using, cos (90 o  - A) = sin A = (sin 2  38 o  + cos 2  38 o ) sin 30 o  + cos 60 o tan45 o sec 60 o

    Using, sin 2  A + cos 2  A = 1

    = {1 X (1/2) } + {(1/2) X 1 X 2} = (1/2) + 1 = (3/2)

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