已知函数f(x)=4sinxcos(x+派/6)+1.求f(x)最小正周期.

问题描述:

已知函数f(x)=4sinxcos(x+派/6)+1.求f(x)最小正周期.

f(x)=4sinxcos(x+派/6)+1。
=2[sin(2x+π/6)+sin(-π/6)]+1
=2sin(2x+π/6)
所以
周期为:π。

f(x)=4sinxcos(x+π/6)+1
=4sinx[(√3/2)cosx-(1/2)sinx]+1
=2√3sinxcosx-2sin²x+1
=√3sin(2x)+cos(2x)
=2sin(2x+π/6)
所以最小正周期为
2π/2=π

f(x)=4sinxcos(x+π/6)+1
=2[sin(2x+π/6)+sin(-π/6)]+1 积化和差公式
=2sin(2x+π/6)
T=2π/2=π