So when a is the first quadrant angle, cosa=2 (root number 2)/3, tana= (root number 2)/4,
Original formula = [1-2x (1/3) x (radical number 2)/3]/[2x (radical number 2/3) 2- 1] [1- (radical number 2)/4]
= ......
When a is the second quadrant angle, cosa=-2 (root number 2)/3, tana=- (root number 2)/4,
Original formula = ......