Question

    sin1440° - cot630° - sin120°cos150° is equal

    to:
    B 1 Correct Answer Incorrect Answer
    C 1/4 Correct Answer Incorrect Answer
    D 3/4 Correct Answer Incorrect Answer

    Solution

    sin1440°  - cot630°  - sin120° cos150°  
    = sin(4 X 360°  + 0°) - cot(2 X 360°  - 90°) - sin(180°  - 60°)cos(90° + 60°)

    = sin0 o  + cot90 o  + sin60 o sin60 o

    = 0 + 0 + (√3/2) 2 = (3/4)

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