在进行三角函数求解时,运用基本公式运算和三角变换,若将题设或结论视为整体,通过对这个整体结构的调节或转化,可使问题解答简洁,推进思维层次. 1.视复角的函数值为整体求解 例1 若θ∈[-π/12,π/12],则函数y=cos(π/4+θ)+sin2θ的最小值是(). (A)0(B)1 (C)9/8(D)3～(1/3)-1/2 When the trigonometric function is solved, basic formula calculations and trigonometric transformations are used. If the questions or conclusions are regarded as a whole, the adjustment of the whole structure can be used to simplify the problem and advance the level of thinking. The value of the function is the overall solution. Example 1 If θ∈[-π/12,π/12], the minimum value of the function y=cos(π/4+θ)+sin2θ is (). (A)0 (B) 1 (C) 9/8 (D) 3 to (1/3)-1/2