-1=sinx+cosx=√2sin(x+π/4)
sin(x+π/4)=-√2/2
x+π/4=2kπ-π/4或-3π/4,
x=2kπ-π2或-π,
sinx=-1或0,cosx=0或-1,sin2009x+cos2011x=(-1)^2009+0^2011=-1或=0^2009+(-1)2011=-1.
-1=sinx+cosx=√2sin(x+π/4)
sin(x+π/4)=-√2/2
x+π/4=2kπ-π/4或-3π/4,
x=2kπ-π2或-π,
sinx=-1或0,cosx=0或-1,sin2009x+cos2011x=(-1)^2009+0^2011=-1或=0^2009+(-1)2011=-1.