Plz tell fast
 

Q.    ​A ladder rests against a wall at an inclination of $\alpha$ to the horizontal. It's foot is pulled away from the wall through a distance 'p' so that its upper end slides a distance 'q' down the wall and then the ladder makes an angle $\beta$ to the horizontal. Show that :-

                                                             $\frac{p}{q} = \frac{\cos \beta - \cos \alpha }{\sin \alpha - \sin \beta }$