来自林捷的问题
函数f(x)=log0.5(cos2x+sin2x)的递减区间是?答案是(kπ-π/8,kπ+π/8)
函数f(x)=log0.5(cos2x+sin2x)的递减区间是?
答案是(kπ-π/8,kπ+π/8)
1回答
2020-05-20 18:11
函数f(x)=log0.5(cos2x+sin2x)的递减区间是?答案是(kπ-π/8,kπ+π/8)
函数f(x)=log0.5(cos2x+sin2x)的递减区间是?
答案是(kπ-π/8,kπ+π/8)
cos2x+sin2x=(根号2){[(根号2)/2]cos2x+[(根号2)/2]sin2x}=(根号2)sin(2x+π/4)f(x)=log0.5(cos2x+sin2x)=log0.5[(根号2)sin(2x+π/4)]要使函数有意义,则sin(2x+π/4)>0,即kπ-π/8≤x≤kπ+3π/8,k为整数对于y=si...