(a) The equation can be represented as intersection points of the two curves and . Which of the following graphs below represents the equation as intersection points of these two curves on the interval ?

A   B   C   D

(b) According to the graph you chose above, there are solutions to this equation on the interval .

(c) Solve for all possible .

Solutions with smaller positive base angle: +
Solutions with larger positive base angle: +

where is any integer, and the base angles are the two smallest positive base angles.

(d) Use your answer to parts (a)-(c) to solve for in . Enter your answers as a comma separated list.

For parts (c) and (d), use radian measure and enter your answers using at least four significant digits.