已知函数f(x)=cos(2x-π/3)+2sin(x-π/4)求函数在区间[0,π/2]上的值域求函数单调区间打错了...f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/29 03:33:01
已知函数f(x)=cos(2x-π/3)+2sin(x-π/4)求函数在区间[0,π/2]上的值域求函数单调区间打错了...f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)
xSJ@,3vR&GJ*Dn *6ZPU㫤Ԭ Νi q3^n{ AEK=ZHrW(HGrޏ~i] 6Fg y3scToWף($p$/oDFm,4sVj`dڿ,Uk$p9 ΉD O1 FJ3ewJ`ii*%w BtEeΫ:N!tLMar aAsmC k2(e~/2`QM/

已知函数f(x)=cos(2x-π/3)+2sin(x-π/4)求函数在区间[0,π/2]上的值域求函数单调区间打错了...f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)
已知函数f(x)=cos(2x-π/3)+2sin(x-π/4)求函数在区间[0,π/2]上的值域
求函数单调区间
打错了...f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)

已知函数f(x)=cos(2x-π/3)+2sin(x-π/4)求函数在区间[0,π/2]上的值域求函数单调区间打错了...f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)
f(x)=cos(2x-π/3)+2sin(x-π/4)sin(x+π/4)=cos(2x-π/3)+2sin(x-π/4)cos[π/2-(x+π/4)]
=cos(2x-π/3)+2sin(x-π/4)cos(x-π/4)=cos(2x-π/3)+sin(2x-π/2)
=cos(2x-π/3)+cos2x=2cos(2x-π/6)cosπ/6=√3cos(2x-π/6)
∵x∈[0,π/2] ∴2x-π/6∈[﹣π/6,5π/6] ∴f(x)∈[﹣3/2,√3]
∴当2x-π/6∈[2kπ,2kπ+π] 即x∈[kπ+π/12,kπ+7π/12] 时,单调递增
当2x-π/6∈[2kπ+π,2kπ+2π] 即x∈[kπ+7π/12,kπ+13π/12] 时,单调递减