上一讲复习 Pn(cosb)为勒让德函数 P(cos(x))=1 P(x=x P(cos(x))=cos(x) P2(x)=(3x2-1)P2(cos(x)=(3cos2(x)-1) P(x)=-(5x'-3x) P(cos(x))=-(5 cos(x)-3cos(x)) P(x)2.1! dx 日才描怅派山东大学物理学院 宗福建 5 上一讲复习 • Pn（cosθ）为勒让德函数 0 0 1 1 2 2 2 2 3 3 3 3 2 ( ) 1 (cos( )) 1 ( ) (cos( )) cos( ) 1 1 ( ) (3 1) (cos( )) (3cos ( ) 1) 2 2 1 1 ( ) (5 3 ) (cos( )) (5cos ( ) 3cos( )) 2 2 1 ( ) ( 1) 2 ! l l l l l P x P x P x x P x x P x x P x x P x x x P x x x d P x x l dx = = = = = − = − = − = − = −