CAN PLAY!

问题描述:

CAN PLAY!
已知向量AB=(1-tanx,1+tanx),AC=(sin(x-π/4),sin(x+π/4))
(1)求证AB⊥AC
(2)若x∈(-π/4,π/4),求│ BC │的取值范围.

向量AB+向量AC=0,就可以证明AB⊥AC