Minimum glare from reflected sunlight [closed]

I'm studying for the IB Physics HL exam, and I came across a question neither my physics teacher or I can solve. It has a diagram like so:

The text of the question is this:

A person wearing polarizing sunglasses stands at the edge of a pond in bright sunlight. The surface of the pond is flat and the line of sight of the person makes an angle theta with the surface. The refractive index of the pond water is $n$. What is the value for theta for which the intensity of the sunlight reflected by the surface to the person's eye a minimum?

The answer is $\arctan\left(\dfrac1n\right)$, and I'm not sure how to even really start.

I think I'm missing a key formula, but I don't know what.

closed as off-topic by Jim, Kyle Kanos, ACuriousMind♦, Rob Jeffries, NeuneckAug 13 '15 at 9:36

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "Homework-like questions should ask about a specific physics concept and show some effort to work through the problem. We want our questions to be useful to the broader community, and to future users. See our meta site for more guidance on how to edit your question to make it better" – Jim, Kyle Kanos, ACuriousMind, Rob Jeffries, Neuneck
If this question can be reworded to fit the rules in the help center, please edit the question.

• Seems quite a tough question. You need to know the orientation of the polariser I think. The reflected light can be split into two perpendicular polarisations, each with a reflection coefficient that depends on theta. One of these goes through a minimum of zero at the Brewster angle, but the other monotonically increases with theta. See Fresnel Equations and tube.geogebra.org/material/show/id/325541 – Rob Jeffries Aug 10 '15 at 21:24