f(x)=sinx-cosx+1
=√2[sinx·(√2/2)-cosx·(√2/2)]+1
=√2(sinx·cosπ/4-cosx·sinπ/4)+1
=√2sin(x-π/4)+1
∴函数的最小正周期T=2π.
∵-1≤sin(x-π/4)≤1
-2≤2sin(x-π/4)≤2
-2+1≤2sin(x-π/4)+1≤2+1
-1≤2sin(x-π/4)+1≤3
∴值域是[-1,3]
f(x)=sinx-cosx+1
=√2[sinx·(√2/2)-cosx·(√2/2)]+1
=√2(sinx·cosπ/4-cosx·sinπ/4)+1
=√2sin(x-π/4)+1
∴函数的最小正周期T=2π.
∵-1≤sin(x-π/4)≤1
-2≤2sin(x-π/4)≤2
-2+1≤2sin(x-π/4)+1≤2+1
-1≤2sin(x-π/4)+1≤3
∴值域是[-1,3]