已知x∈R,f(x)=1/2sin²x(1/tanx/2-tanx/2)+√3/2cos2x
问题描述:
已知x∈R,f(x)=1/2sin²x(1/tanx/2-tanx/2)+√3/2cos2x
已知x∈R,f(x)=1/2*sin²x(1/tanx/2-tanx/2)+√3/2*cos2x
1.若0<x<π/2,求f(x)的单调的递减区间
2.若f(x)=√3/2,求x的值
答
f(x)=(sinx)^2/2*(1/tan(x/2)-tan(x/2))+√3/2cos2x
=(sinx)^2[(cos(x/2))^2-(sin(x/2))^2]/[2sin(x/2)cos(x/2)]+√3/2cos2x
=(sinx)^2cosx/sinx+√3/2cos2x
=(1/2)(sin2x)+(√3/2)cos2x
=sin(2x+π/3)
π/2f(x)=(sinx)^2/2*(1/tan(x/2)-tan(x/2))+√3/2cos2x=(sinx)^2[(cos(x/2))^2-(sin(x/2))^2]/[2sin(x/2)cos(x/2)]+√3/2cos2x我不太懂 能分开解释一下么?