Bruce often____(do)his homework in the evening.But yesterday evening he____(watch)TV.
已知直线y=ex+1与曲线y=ex+a相切(e是自然对数的底数),则a的值是( )
若一段圆弧的长度等于该圆内接正三角形的边长,则这段弧所对圆心角弧度为( )