How to Calculate d(theta0)/d(theta1) in Snell's Law?

[ytht100]

I have light incident from plane with velocity v0 into plane with velocity v1. Obviously, according to Snell's law, v0/v1=sin(theta0)/sin(theta1), where theta0 and theta1 are the angles with regard to the vertical line. How to calculate d(theta0)/d(theta1)? There are probably arguments from geometry and analysis.
Thanks a lot!

 

[jtbell]

First, for simplicity write v₀/v₁ = R. Then

R sin θ₁ = sin θ₀

Now take the derivative of each side with respect to θ₁. On the right-hand side, θ₀ is a function of θ₁. What rule does that suggest?

 

[ytht100]

Thanks a lot! That was clear!