Prove that the magnitude of the impact parameter B equals the length (-b) of the hyperbolic semiminor axis.
The Attempt at a Solution
I really don't know where to start. I was thinking of finding a relation between a and b but that is just the right hand side of the equation above (for hyperbolic geometry). I was thinking about the Pythagorean theorem, but then I don't know how |B|=|a+b| would become |a|sqrt(e^2-1). Could anyone help me along the right direction? Thanks.