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


    Question

    If cos2B = sin(2B - 30°), then find the measure of 'B'.

    A 14° Correct Answer Incorrect Answer
    B 30° Correct Answer Incorrect Answer
    C 36° Correct Answer Incorrect Answer
    D 26° Correct Answer Incorrect Answer

    Solution

    We know that, cosA = sin(90° - A) cos2B = sin(2B - 30°) Or, sin(90° - 2B) = sin(2B - 30°) Or, 90° - 2B = 2B - 30° Or, 2B + 2B = 90° + 30° So, B = (120° / 4) = 30°

    Practice Next
    ask-question