sin(x+派/6)=2/3 则sin(19派/6+x)+sin^2(派/3-x)的值域

问题描述:

sin(x+派/6)=2/3 则sin(19派/6+x)+sin^2(派/3-x)的值域

原式=sin(7/6*π+x)+{sin[π/2-(π/6+x)]}^2
=-sin(π/6+x)+[cos(π/6+x)]^2
=-2/3 +1-[sin(π/6+x)]^2
=1/3-(2/3)^2=-1/9