已知函数f(x)=-√3sin^x+sinxcosx,x∈R(1)求函数f(x)的最小正周期(2)求函数x∈【0,π/2】值域
已知函数f(x)=-√3sin^x+sinxcosx,x∈R(1)求函数f(x)的最小正周期(2)求函数x∈【0,π/2】值域
f(x)=-√3(sinx)^2+sinxcosx
=-√3/2*(1-cos2x)+1/2*sin2x
=1/2*sin2x+√3/2*cos2x-√3/2
=sin(2x+π/3)-√3/2
1
最小正周期为 π
2
因为 0≤x≤π/2,所以 π/3≤2x+π/3≤π+π/3
所以 -√3/2≤sin(2x+π/3)≤1
因此,函数的值域是 【-√3,1-√3/2】。
f(x)=-√3sin^x+sinxcosx
=-(√3/2)(1-cos2x)+(1/2)sin2x
=-(√3/2)+(1/2)(sin2x+√3cos2x)
=sin(2x+π/3)-√3/2
T=2π/2=π
x∈[0,π/2]
2x∈[0,π]
2x+π/3∈[π/3,4π/3]
-√3/2-√3所以f(x)∈[-√3,1-√3/2]
1,f(x)=-√3sin^2x+sinxcosx=√3/2*(cos2x-1)+1/2sin2x=√3/2cos2x+1/2sin2x-√3/2=cos(2x-π/6)-√3/2,最小正周期 T=2π/2=π,2,x∈【0,π/2】,则2x-π/6∈【-π/6,5π/6】当2x-π/6=0时,f(x)取最大值1-√3/2,...
f(x)=-√3sin^2x+sinxcosx
=-√3(1-cos2x)/2+1/2sin2x
=-√3/2+1/2(cos2x+sin2x)
=-√3/2+√2/2(√2/2cos2x+√2/2sin2x)
=-√3/2+√2/2sin(π/4+2x)
因此,其周期是π
x∈[0,π/2]
2x+π/4∈[π/4,5/4π]
-√2/2≤sin(π/4+2x)≤1
-1/2≤√2/2sin(π/4+2x)≤√2/2
-1/2-√3/2≤-√3/2+√2/2sin(π/4+2x)≤√2/2 -√3/2