関連ワード:  what is 1 - cos 2x    what is 1 - cos 2x / 2    what is 1 cos 2x equal to    what is 1 cos 2x identity    what is 1 cos 2x formula    what is 1 cos 2x trig identity    what is 1 cos 2x in terms of sin    what is integral of 1 cos 2x    what is 1 cos 2x sin 2x    what is value of 1 cos 2x