📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!

    âš¡ Month End Offer - Flat 52% Off On All Courses! Enroll Now âš¡
    00:00:00 AM Left

    Question

    If cos2B = sin(1.5B + 27 o), then find the

    measure of 'B'. 
    A 12° Correct Answer Incorrect Answer
    B 15° Correct Answer Incorrect Answer
    C 18° Correct Answer Incorrect Answer
    D 21° Correct Answer Incorrect Answer

    Solution

    We know that, cosA = sin(90 o - A) cos2B = sin(1.5B + 27 o) Or, sin(90 o - 2B) = sin(1.5B + 27 o) Or, 90o - 2B = 1.5B + 27 o Or, 2B + 1.5B = 90 o - 27 o So, 3.5B = 63 o So, B = (63 o/ 3.5) = 18 o Hence, option c.

    Practice Next
    More Trigonometry Questions
    ask-question