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1986 Iran MO (2nd round)
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The arctangent function - [Iran Second Round 1986]
The arctangent function - [Iran Second Round 1986]
Source:
December 24, 2010
function
algebra proposed
algebra
Problem Statement
Prove that
arctan
1
2
+
arctan
1
3
=
π
4
.
\arctan \frac 12 +\arctan \frac 13 = \frac{\pi}{4}.
arctan
2
1
+
arctan
3
1
=
4
π
.
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