New RBI Grade B 2025 Notification will come Soon! Enroll Here

    Question

    If (sin 3A sec 6A = 1) , then what will be the value of

    cos 6A?
    B √3/2 Correct Answer Incorrect Answer
    C 1 Correct Answer Incorrect Answer
    D 1/2 Correct Answer Incorrect Answer

    Solution

    sin 3A sec 6A = 1 Or, sin 3A = (1/sec 6A) We know that, sec P is the reciprocal of cos P Or, sin 3A = cos 6A We know that, cos P = sin (90 - P) Or, sin 3A = sin (90 - 6A) Or, 3A = 90 - 6A Or, 9A = 90 So, 'A' = 10 Required value = cos 6A = cos 60o = (1/2)

    Practice Next