y=(sinx)的平方+2sinxcosx+3(cosx)的平方
=(sinx)^2+sin2x+(cosx)^2+2(cosx)^2
=1+sin2x+cos2x+1
=sin2x+cos2x+2
=(根号2)*sin(2x+pi/4)+2
所以最小正周期T=2*pi/2=pi
"pi"代表"圆周率"
y=(sinx)的平方+2sinxcosx+3(cosx)的平方
=(sinx)^2+sin2x+(cosx)^2+2(cosx)^2
=1+sin2x+cos2x+1
=sin2x+cos2x+2
=(根号2)*sin(2x+pi/4)+2
所以最小正周期T=2*pi/2=pi
"pi"代表"圆周率"