Question

高一数学试卷函数题有什么技巧啊

Answer 1

因为（4x+π/3）和（π/6-4x）互余
cos(π/6-4x)=sin(4x+π/3)
则y=2sin(4x+π/3)
当2k
π
-π/2≤
4x+π/3≤2k
π
+π/2
时
即1/2k
π-
5π/24
≤x≤
1/2k
π+π/24
y单调递增
当2k
π
+π/2≤4x+π/3≤2k
π+3π/2时
即1/2k
π+π/24
≤x≤
1/2k
π+7π/24
y单调递减
当4x+π/3=2k
π
+π/2
时
y取最大值
x=1/2k
π+π/24
x∈｛x|x=1/2k
π+π/24，k
∈z｝