Question

Find the measures of two angles, one positive and one negative that are coterminal with pi/5

Answer 1

To find coterminal angles for an angle, β, given in radians use the following formula:
                                  coterminal angle =  β + 2πk
                          where k is an integer {..., -3, -2, -1, 0, 1, 2, 3, ...}
Negative Coterminal Angle: k = -1 
                                   NCA = π/5 + 2π(-1)
                                            = -9π/5      
Positive Coterminal Angle: k = 1
                                  PCA = π/5 + 2π(1)
                                           = 11π/5
The following answers are just one of many possible answer... you have infinite number of choices for k.
$NCA = \frac{-9 \pi }{5}$
$PCA= \frac{11 \pi }{5}$