12/11/30 17:16:04.26
一般に
|sin(t+nπ)| = |(（-1）＾ｎ)*sin(t)| = |（-1）＾ｎ|*|sin(t)| = |sin(t)|
0≦t≦πのときは sin(t)≧0 なので
|sin(t)| = sin(t)
12/11/30 17:16:04.26
一般に
|sin(t+nπ)| = |(（-1）＾ｎ)*sin(t)| = |（-1）＾ｎ|*|sin(t)| = |sin(t)|
0≦t≦πのときは sin(t)≧0 なので
|sin(t)| = sin(t)