1,Ex,y∈R,有：.(x+y)^2=0,可推出:∨x,y∈R.(x+y)^2≥4xy
2.:∨x,∈R,sinx+cosx≠√3,.真命题：√3=sinx+cosx=√2sin(x+45*)
sin(x+45*)=√1.5>1