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

  • google app store apple app store
  • ✖

      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