Tutorial 11, exercise 3, question 4

Calculating the minima and bandwidths of the band obtained from the nearly free electron model, i understand that the bandwidth is E(kmax)-E(kmin). why is the bandwidth then given by E(pi/2)-E(0)? why is kmax pi/2 instead of pi/a?

I hope someone could help me explain this:) that would be really helpful!

You’re right, it’s a typo; fixed now.