Question 53
Calculate the sum
$$
\sum_{n=1}^{2012} \operatorname{tg} n \operatorname{tg} (n + 1).
$$
$$
\sum_{n=1}^{2012} \operatorname{tg} n \operatorname{tg} (n + 1).
$$
MathNet 2012 Question 53
Math Olympiad Vault · MathNet 2012
Math Olympiad Vault · MathNet 2012