Finding $\sin 2x+\sin 4x+\cdots+\sin 22x$
5080
How can we sum up $\sin$ and $\cos$ series when the angles are in arithmetic progression?
51787
Evaluate $\int \cos(3x) \sin(2x) \, dx$.
4547
How to solve $\frac{1}{1000.1998}+\frac{1}{1001.1997}+\cdots+\frac{1}{1998.1000}$
105487
Prove that $\sin x \cdot \sin (2x) \cdot \sin(3x) < \tfrac{9}{16}$ for all $x$
17102
If $\left(1+\sin \phi\right)\cdot \left(1+\cos \phi\right) = \frac{5}{4}\;,$ Then $\left(1-\sin \phi\right)\cdot \left(1-\cos \phi\right)$
17168
Find the value of $\sin\frac{2\pi}{7}+\sin\frac{4\pi}{7}+\sin\frac{8\pi}{7}$
1210
Write an expression for $(\cos θ + i\sin θ)^4$ using De Moivre’s Theorem.
106441
Find the value of $\binom{2000}{2} + \binom{2000}{5} + \binom{2000}{8} + \cdots \binom{2000}{2000}$
23576
Calculating $1+\frac13+\frac{1\cdot3}{3\cdot6}+\frac{1\cdot3\cdot5}{3\cdot6\cdot9}+\frac{1\cdot3\cdot5\cdot7}{3\cdot6\cdot9\cdot12}+\dots? $
73538
solving $\cos z + \sin z = i$
105496
Need help solving - $ \int (\sin 101x) \cdot\sin^{99}x\,dx $
53135
Find $4\cos\theta-3\sin\theta$, given that $4\sin \theta +3\cos \theta = 5$
59014
Prove that $\sin(2A)+\sin(2B)+\sin(2C)=4\sin(A)\sin(B)\sin(C)$ when $A,B,C$ are angles of a triangle
12414
prove that : $\cos x \cdot \cos(x-60^{\circ}) \cdot \cos(x+60^{\circ})= \frac14 \cos3x$
135225
How to find the period of the sum of two trigonometric functions
120569
Trigonometric Functions And Identities Question .
89319
How can I find all the solutions of $\sin^5x+\cos^3x=1$