For a plane wave with perpendicular polarization obliquely incident from region 1 onto the boundary with region 2, what is the value of the reflection coefficient at the Brewster angle of incidence? Type your answer to three places after the decimal. Include the negative sign if your answer is negative. Reminder: At the Brewster angle of incidence, the reflection coefficient for parallel polarization is zero. However, this question is asking for the value of the reflection coefficient for perpendicular polarization. Assume region 1 (z 0) is free space.