1 1.d all the points on the diagonal of the square B 1D meet the question, so there are countless points.

Pay attention to the application of particularity to general ideas.

12, b is bB 1 ⊥ y in b1,and a is AA 1⊥L, | bb 1 | = m/e, |

| am | = | aa 1 |-| bb 1 | = 2m/e，let ∠ baa 1 = θ，cosθ= | am |/| ab | = 2/4e = 1/2e = 65438。

So k=tanθ=√2.