设w>0,若函数f[x]=2sinwx在[-π3,π4]上单调递增,则w的取值范围是
解析:∵函数f[x]=2sinwx(w>0)在[-π3,π4]上单调递增
f(x)单调增区间:wx∈[2kπ-π/2,2kπ+π/2]==>x∈[2kπ/w-π/(2w),2kπ/w+π/(2w)]
区间[-π/3,π/4]包含于[2kπ/w-π/(2w),2kπ/w+π/(2w)]
∴-π/(2w)-1/(2w)w=π/4==>1/(2w)>=1/4==>w
设w>0,若函数f[x]=2sinwx在[-π3,π4]上单调递增,则w的取值范围是
解析:∵函数f[x]=2sinwx(w>0)在[-π3,π4]上单调递增
f(x)单调增区间:wx∈[2kπ-π/2,2kπ+π/2]==>x∈[2kπ/w-π/(2w),2kπ/w+π/(2w)]
区间[-π/3,π/4]包含于[2kπ/w-π/(2w),2kπ/w+π/(2w)]
∴-π/(2w)-1/(2w)w=π/4==>1/(2w)>=1/4==>w