# A (probably) simple question about Bell's paper

## Summary:

Specifically, the demonstration of a single-particle hidden variable
Hello! I am trying to understand Bell's Inequality and although I can follow the arguments of the inequality as are mentioned in modern texts, something was always bothering me. In section III (Illustration) of the original paper, equation (5) states:

< σ⋅a > = 1 - 2θ'/π​

But for the life of me, I don't know why, and I am not sure how to assemble this by hand, it seems like everywhere I find similar values there's just a "well, obviously this gives: " followed by the above. Trying to put together the integral has me wondering if B(b,λ) is just to be taken as 1? Maybe it's been too long since I did any calculus...