Why is $e^{-i\theta} = \cos \theta -i\sin \theta$?
55869
Use the Maclaurin series to prove that $e^{i\theta} = cos(\theta) + isin(\theta)$
5747
$\cos(\arcsin(x)) = \sqrt{1 - x^2}$. How?
40837
Why $e^{i(π/3)} \ne -1$?
108995
Prove $|e^{i\theta} -1| \leq |\theta|$
157364
$\int_{-2}^{2} \sin(x^5)e^{(x^8\sin(x^4))} dx$
124209
How is $\ln(-1) = i\pi$?
82586
Why is cos -x equal to cos x?
31102
Why does $\frac{1}{r}\frac{dr}{d\theta} = \cot \psi$?
39697
Integration of $e^{ax}\cos bx$ and $e^{ax}\sin bx$
35454
Is it correct to write $\Bbb E[X]$ or $\Bbb E_{\theta}[X]$?
10289
Need help in proving that $\frac{\sin\theta - \cos\theta + 1}{\sin\theta + \cos\theta - 1} = \frac 1{\sec\theta - \tan\theta}$
117680
Prove that $|e^{i\theta_1}-e^{i\theta_2}| \leq |\theta_1 - \theta_2|$
103987
What does the square root of minus $i$ equal?
117200
Evaluation of $ \sum_{k=0}^n \cos k\theta $
104410
Why do we omit the negative sign when finding basic angle when solving trigonometric equations?
55436
Why does $A\sin{k(x+c)}=a\sin{kx}+b\cos{kx}$ imply that $A=\sqrt{a^2+b^2}$ and $\tan{c}=-b/a$?
44400
$e^{2\pi i x} = (e^{2\pi i})^x$: What happens if x is rational?