oK SO... I have been given the task of deriving the Compton effect equ. ( \lambda\prime-\lambda=\frac{h}{m_ec}(1-cos\theta))
exactly from the 3 following:
1) \frac{h}{\lambda}=\frac{h}{\lambda\prime}cos\theta +\gamma m u cos\phi
2) 0=\frac{h}{\lambda\prime}sin\theta-\gamma mu sin\phi...