tify"> 3 + N 4 + N 5 span> )
2) 1/X 1 = (N 1 + N 2 + N 3 + N 4 + N 5 )/N 1 span> = 1 + k 1 + k 2 + k 3 + k 4
1/X 2 = (N 1 span> + N 2 + N 3 + N 4 + N 5 )/N 2 = (1/ k 1 ) +1 + k 5 + k 6 + k 7
/X 3 = (N 1 + N 2 + N 3 + N 4 + N 5 )/N 3 = (1/< i align = "justify"> k 2 ) + (1/ k 5 ) +1 + k 8 + k 9
/X 4 = (N 1 + N 2