1. the inverse function is to use the function Y=2x+3/x- 1 to get x, x=y+3/y-2, and then use y = x+3/X≠2) 2, (x.a1+a6 = Let these three numbers be A-D, A and A+D, then A-D+A+D =18 (A-D)+A+(A+D) =116, so these three numbers get a = 6, D. 8 ① sum of the top n items in arithmetic progression: a1=14.5d = 0.7an = 32an = a1+(n-1) d, that is, 32 =14.5+(n-/kloc-0). The tolerance is-1an = 5+(n-1) (-1) = 6-n sn = (a1+an) n/2 = (5+6-n) n/2 =-30.