Summing up trigonometric series
5080
How can we sum up $\sin$ and $\cos$ series when the angles are in arithmetic progression?
84846
Convergence of cos, sin, tan functions
35036
Series $\sum_{n=1}^{\infty}\frac{\cos(nx)}{n^2}$
62271
Find the sum of the series: $\cos^3 \alpha +\cos^3 {3\alpha} + \cos^3 {5\alpha}+....+\cos^3 {(2n-1)\alpha}$.
81102
Cosine of the sum of two solutions of trigonometric equation $a\cos \theta + b\sin \theta = c$
94871
Sum of an unorthodox infinite series
42424
Riemann sum of $\sin(x)$
138847
Tricky trigonometric sum evaluation
6634
Evaluate trigonometric function
31731
How to turn this into an equation and then sum the series?
148883
Sum of the series $\frac{1}{2\cdot 4}+\frac{1\cdot3}{2\cdot4\cdot6}+\dots$
65492
Basic Geometric Series
112036
sum of series $\frac{n}{1\cdot 2 \cdot 3}+\frac{n-1}{2\cdot 3\cdot 4}+\frac{n-2}{3\cdot 4 \cdot 5}+\cdots \cdots n$ terms
67271
$\sum_{n=-\infty}^{\infty}\frac{1}{(u +n)^2}=\frac{\pi^2}{(\sin \pi u)^2}$
138492
Finding the sum of the infinite series whose general term is not easy to visualize: $\frac16+\frac5{6\cdot12}+\frac{5\cdot8}{6\cdot12\cdot18}+\cdots$
95739
Sum of tangent functions where arguments are in specific arithmetic series
141645
Trigonometric series sum proof