2cosinX = 2 + (sinX)^2
2cosinX = 2 + [1 - (cosinX)^2]
(cosinX)^2 + 2cosinX - 3 = 0
(cosinX - 1) (cosinX +3) = 0
cosinX = 1 [since (cosinX +3) is always greater than zero]
X = [arc cosin(1)] or 2n times pi where n being an integer
2008-08-05 01:11:51 補充:
According to the question, x cannot be in degree(s). The angle x rfers to should be in radian measure. Therefore I do not consider the above two calculation gave the corect answer at this moment 1:11am Hongkong time.