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

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

    Question

    If tan A = 1 and tan B = √ 3, what is the value of cos

    A . cos B - sin A . sin B?
    A (1 + √3)/2√2 Correct Answer Incorrect Answer
    B (1 - √3)/2√2 Correct Answer Incorrect Answer
    C 2√2/3 Correct Answer Incorrect Answer
    D 1 Correct Answer Incorrect Answer

    Solution

    Given, tan A = 1 ⇒ A = 45° Also given, tan B = √ 3 ⇒ B = 60° ∴ cos A . cos B - sin A . sin B = cos 45° . cos 60° - sin 45° . sin 60° = 1/ √ 2 * 1/2 - 1/ √ 2 . √ 3/2 = (1 - √ 3)/2 √ 2

    Practice Next
    More Trigonometry Questions