已知向量a=(2cosx/2,tan(x/2+π/4)),b=(√2sin(x/2+π/4),tan(x/2-π/4))
1个回答

f(x)=2cosx/2×(√2sin(x/2+π/4)+ tan(x/2+π/4)×tan(x/2-π/4))

=√2[sin(x+π/4)+sin(π/4)] + [1+tan(x/2)]/[1-tan(x/2)]×[tan(x/2)-1]/[1+tan(x/2)]

=√2sin(x+π/4)

最大值=√2

最小正周期=2π

sinx的增区间是:-π/2+2kπ≤x≤π/2+2kπ

带入-π/2+2kπ≤x+π/4≤π/2+2kπ

所以增区间-3π/4+2kπ≤x≤π/4+2kπ

减区间同理

如有不懂请追问或HI我

谢谢采纳!