设直线kx+(k+1)y=1(k为自然数)与两坐标轴所围成的图形的面积为Sk(k=1,2,3,…,2000).则S1+S2+S3+…+S2000=______.
如图:直线kx+(k+1)y=1(k为正整数),与x轴的交点坐标为(
,0),与y轴的交点坐标为(0,1 k
).1 k+1
则S△ABO=
×1 2
×1 k
,1 k+1
S1=
;1 2×2
S2=
,1 2×2×3
…
S2000=
,1 2×2000×2001
S1+S2+S3+…+S2000=
+1 2×2
+…+1 2×2×3 1 2×2000×2001
=
(1 2
+1 1×2
+…+1 2×3
)1 2000×2001
=
(1-1 2
+1 2
-1 2
+1 3
-1 3
+…1 4
-1 2000
)1 2001
=
.1000 2001
故答案为:
.1000 2001