f(x)=(根号下2)*sin[(pai/4)+x]根据公式sin（A+B）=sinAcosB+cosAsinB得出来f（x）=sinx+cosxf（x）=sinx+cosx≥1/2sinˇ2x+2sinxcosx+cosˇ2≥1/41+sin(2x)≥1/4sin(2x)≥-3/42x≥arcsin(-3/4)+2πx≥[arcsin(-3/4...