I thought it was a full-wave because the top diode conducts when the voltage is positive, then the bottom diode conducts when the voltage is negative (reverse-biased). I checked my old Electronics books and for a half-wave rectifier they are only showing one diode for the rectifier circuit.
I got an answer very close to CI book using the integration method.
I think the way CI drew the rectifier is somewhat confusing. With the way they drew the circuit, you just have to think through the operation as the voltage signal changes. Hopefully, I am not leading us both astray but I think that is correct.
EDIT #1: If it is indeed a half-wave rectifier, then your equation is correct.
EDIT #2: Look at Problem 71. I think that is the half-wave rectifier.