1) The range of the function f (x) = 12−cos3x is A) (-2, 8) B) [-2,3] C) [1/3, 1] D) (1/2,1) Answer: Option CExplanation:We have - 1≤ cos 3x≤ 1 = - 1 ≤-cos 3x≤ 1 Add '2' on both sides 1≤ 2 - cos 3x ≤ 3 1 ≥ 12−cos3x ≥ 1/3
