(a) Find the wavelength of the incident photon.

(b) Find the angle at which the photon is scattered.

(c) Find the angle at which the electron recoils.

i did the calculation found that at:

a) that the wavelength of the incident photon is 0.0953846x10^-10 m

b) i m reaching an answer 1-cosO=2.0809 that is wrong since it s >1 it should be <1

is the question wrong or the calculation at b?