y=Sin(π/4-2x)的单调区间?.

y=sin(π/4-2x)=sin[π-(π/4-2x)]=sin(2x-3π/4)=sin2(x-3π/8)
y=sin2(x-3π/8)的图象即由y=sinx的图象横坐标缩小一倍，向右平移3π/8个单位得到
y=sinx的单调递增区间(2kπ-π/2，2kπ+π/2)，单调递减区间(2kπ+π/2，2kπ+3π/2)
y=sin2x的单调递增区间(kπ-π/4，kπ+π/4)，单调递减区间(kπ+π/4，kπ+3π/4)
y=sin2(x-3π/8)的单调递增区间(kπ+π/8，kπ+5π/8)，单调递减区间(kπ+5π/8，kπ+9π/8)
即y=sin(π/4-2x)的单调递增区间(kπ+π/8，kπ+5π/8)，单调递减区间(kπ+5π/8，kπ+9π/8)

单调减区间[-π/8+kπ,3π/8+kπ]
单调增区间[3π/8+kπ,7π/8+kπ]

单调减{-1/8PI+kPI,3/8PI+kPI}
其余为单调增

kπ+-π/2 减．．〔Kπ+π／2，kπ+π]增