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National and Regional Contests
Greece Contests
Greece JBMO TST
2007 Greece JBMO TST
4
4
Part of
2007 Greece JBMO TST
Problems
(1)
sum with last term \sqrt{1+(8\cdot 1003^2-1)/(2005^2 2007^2)}
Source: Greece JBMO TST 2007 p4
6/17/2019
Calculate the sum
S
=
1
+
8
⋅
1
2
−
1
1
2
⋅
3
2
+
1
+
8
⋅
2
2
−
1
3
2
⋅
5
2
+
.
.
.
+
1
+
8
⋅
100
3
2
−
1
200
5
2
⋅
200
7
2
S=\sqrt{1+\frac{8\cdot 1^2-1}{1^2\cdot 3^2}}+\sqrt{1+\frac{8\cdot 2^2-1}{3^2\cdot 5^2}}+...+ \sqrt{1+\frac{8\cdot 1003^2-1}{2005^2\cdot 2007^2}}
S
=
1
+
1
2
⋅
3
2
8
⋅
1
2
−
1
+
1
+
3
2
⋅
5
2
8
⋅
2
2
−
1
+
...
+
1
+
200
5
2
⋅
200
7
2
8
⋅
100
3
2
−
1
algebra
Sum
radical