E(t)=ao+>ak cos kat+bk sin katy k=1 E odt+ E sin tdt E sin tdt 2丌 loE E sin ot cos kott=o[sin(1+k)ot+sin(1-k)otdt 2丌 E E sin 2otdt= 0- cos 2ot o=0 4丌 Ed Isin(1+k)ot +sin(1-kotdt 丌 1+k 1-k k=2n+1 Eor cos(1+ k )ot cos(l-kotlxlo Eor 2E 2丌 1+k 1-k 2丌1+k1+k1-k1-k k=2n l1-(2n)2]r  = = + + −             / 0 0 / 0 0 [sin(1 ) sin(1 ) 2 sin cos 1 k t k tdt E a E t k tdt k cos 2 0, 4 sin 2 2 / 0 0 / 0 0 1 = = − =           t E tdt E a      = − = + = − + − − − + + + − = − − − − + + − = + + − + −  2 . [1 (2 ) ] 2 0 2 1 ] 1 1 1 ( 1) 1 1 1 ( 1) [ 2 ] 1 cos(1 ) 1 cos(1 ) [ 2 [sin(1 ) sin(1 ) 2 2 0 1 1 / 0 0 0 / 0 0 k n n E k n k k k k E k k t k E k t k t k tdt E a k k k              ( ) { cos sin } . 1 0 E t a a k t b k t k  k  k   = = + + , 2 sin 2 [ 0 sin ] 2 1 0 / 0 0 0 / / 0 0 0              E a = dt + E tdt = E tdt = −  