Question

Find the co terminal angle for 15pi/4

Answer 1

15π/4 = 675°
which is co-terminal with 675-360 or 315°
or 7π/4

notice that 15π/4 - 2π = 7π/4

Answer 2

Nonnegative coterminal is (pi)/4
Negative coterminal is -(pi)/4