Simplify a quick sum of sines
5080
How can we sum up $\sin$ and $\cos$ series when the angles are in arithmetic progression?
74294
How to simplify $\sum_{i=1}^{k}\binom{n + i - 1}{i}$?
15932
How to simplify the summation kk! without using induction?
138847
Tricky trigonometric sum evaluation
89561
Find the sum of angles without trigonometry?
154231
Solving trigonometric equations without a calculator or tables
45588
Summing a series with a changing power
5432
How can I quickly sum all numbers in a file?
91744
Proving sum of sines is periodic when ratio of their frequencies is rational using differentation
482
Express $1 + \frac {1}{2} \binom{n}{1} + \frac {1}{3} \binom{n}{2} + \dotsb + \frac{1}{n + 1}\binom{n}{n}$ in a simplifed form
31731
How to turn this into an equation and then sum the series?
83332
Trig sum: $\tan ^21^\circ+\tan ^22^\circ+\cdots+\tan^2 89^\circ = \text{?}$
99335
Sum of all triangle numbers
9479
$\sum \cos$ when angles are in arithmetic progression
31575
Solving trigonometric equations of the form $a\sin x + b\cos x = c$
95786
Sum $\frac{1}{6} + \frac{5}{6\cdot 12} + \frac{5\cdot 8}{6\cdot 12\cdot 18} + \frac{5\cdot 8\cdot 11}{6\cdot 12\cdot 18\cdot 24}+\ldots$
13297
Prove the following trigonometric identity without a calculator involved