,L[]CASE ,SIGMA ,EXAMPLES #1_4 ,L[]CASE SIGMA : IS (T5 US$ 6REPRES5T ! /&>D DEVI,N 9 /ATI/ICS IS WRITT5 .S #2_4 ,L[]CASE SIGMA EQUALS F\RTE5 PO9T EIE ROOT ( OP5 FRAC;N UPP]CASE SIGMA OP5 P>5!SIS ;X M9US ;X B> CLOSE P>5!SIS SQU>$ OV] ;N M9US #1 IS WRITT5 .S .K >?.,S(X-X:)^2"/N-1#] #A