Hi,
I can't solve this problem. Can someone help me?

determine two coterminal angles (one positive and one negative) for a) 8pi/4 and b) 8pi/45. give your answer in radians.

Thank you so much!

Isabel

coterminal angles are obtained by adding some multiple of 360 degrees or 2pi radians to the original angle.

a) 8pi/4
a positive coterminal angle is: 8pi/4 + 2pi = 2pi + 2pi = 4pi
a negative coterminal angle is: 8pi/4 - 2*2pi = 2pi - 4pi = -2pi

b) 8pi/45
a positive coterminal angle is: 8pi/45 + 2pi = 98pi/45
a negative coterminal angle is: 8pi/45 - 2pi = -82pi/45

see Find Coterminal Angles for more info