向量a=(m,1),
向量b=(sinx,cosx),
f(x)=a·b=msinx+cosx,
f(π/2)=msin(π/2)+cos(π/2)=m=1,
m=1,
则f(x)=sinx+cosx.,
f(x)=√2[sinx(√2/2)+cosx(√2/2)]
=√2sin(x+π/4),
最小周期=2π,
最大值=√2,x+π/4=2kπ+π/2,当x=2kπ+π/4时有最大值,
最小值=-√2,x+π/4=2kπ+3π/2,当x=2kπ+5π/4时有最小值.