Let z_{0} = a + ic, z_{1} = b + id, z_{2} = -id, and z = [z_{0} + z_{1}]. Let z_{0} be the apex of the wedge with one ray passing through z_{1} and the other passing through z_{2}, and with z in its interior. Suppose φ is a harmonic function in the wedge that contains z, z_{1}, z_{2}, and z_{0}, taking the value -0.5 on the ray passing through z_{1} and the value 1.5 on the ray passing through z_{2}. What, to 3 decimal places, is the value of φ at z?
(Hint: if you can't figure out how to get the right quadrants for your angles, try breaking them into pieces - referencing each piece separately to the nearest axis, +y or -y or -x - so that each piece is between 0 and 90 degrees; then sum them up.)