Derivation of angle of deviation in a prism

[01-cdmg-10]

derivation of an expression for the angle of deviation in a prism, in terms of $$\theta$$a and $$\theta$$g and A

Homework Equations

($$\theta$$a - $$\theta$$g ) + ($$\theta$$a' - $$\theta$$g' ) = D

A = $$\theta$$g + $$\theta$$g'

i get stuck trying to put $$\theta$$a' into the terms the question states, anyone have an idea? thanks,

 

[Martin Rattigan]

You can work out the refractive index from $\theta_a$ and $\theta_g$.