What will be the formula of $2^2 + 4^2 + \dots + n^2$?
16472
Sum of First $n$ Squares Equals $\frac{n(n+1)(2n+1)}{6}$
7063
How to compute the  formula $\sum  \limits_{r=1}^d r \cdot 2^r$?
36361
How to calculate the summation $(\sum_{p = k}^{n} \binom{n}{p}) / 2^n$ quickly?
74143
Simplifying and evaluating $\cot 70^\circ+4\cos 70^\circ$
149685
Formula for $\sqrt{a-\sqrt{a+\sqrt{a+\ldots}}}$
86900
Formula for the $1\cdot 2 + 2\cdot 3 + 3\cdot 4+\ldots + n\cdot (n+1)$ sum
110996
Sum of the form $r+r^2+r^4+\dots+r^{2^k} = \sum_{i=1}^k r^{2^i}$
133420
Computing the binomial series: $\binom{n}{2}\cdot2^2+\binom{n}{4}\cdot2^4+\binom{n}{6}\cdot2^6+\cdots+ \binom{n}{n}\cdot2^n$
122096
Find $GCD(n^2+1,n+1)$
142673
Evaluate $\tan^{2}(20^{\circ}) + \tan^{2}(40^{\circ}) + \tan^{2}(80^{\circ})$
76941
How do you find the value of $\sum_{r=0}^{44} \tan^2(2r+1)$?
75457
How do i simplify the following: $\sum_{i=1}^n (3i^2+4) - \sum_{j=2}^{n+1} (3j^2+1)$
54604
Evaluate $ \sum_{m > n > 0} \frac{m^2 - n^2}{(m^2 + n^2)^2} $
134633
How to sum this series for $\pi/2$ directly?
71591
Formula for completing the square?
151477
computing the series $\sum_{n=1}^\infty \frac{1}{n^2 2^n}$
13085
Evaluate $ 1 + \frac{1}{3}\frac{1}{4}+\frac{1}{5}\frac{1}{4^2}+\frac{1}{7}\frac{1}{4^3}+\dots$