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

    Question

    src="https://www.ixambee.com/questionimage/Chapter/1709968045-21.JPG" alt="" />  what is the value of (cosec² + sec)
    A 9/2 Correct Answer Incorrect Answer
    B 4/3 Correct Answer Incorrect Answer
    C 8/3 Correct Answer Incorrect Answer
    D 5/2 Correct Answer Incorrect Answer

    Solution

    1-tan2 =1/2 tan²   = 1/2 1 + tan²   = 3/2   sec2   = 3/2 .            (1)   cos2   = 2/3 1-cos2   = 1/3   sin2   = 1/3   cosec2   = 3             . (2) Hence (1) + (2), (cosec² + sec² )=3+3/2 =9/2 .. The required value is 9/2.

    Practice Next

    Relevant for Exams: