Why is the e in the LHS equals to cos + isin in the RHS?
742
How to prove Euler's formula: $e^{i\varphi}=\cos(\varphi) +i\sin(\varphi)$?
48881
Verification the integral identity $\int_0^\pi \ln(1+\alpha\cos(x))dx=\pi\ln\left(\frac{1+\sqrt{1-\alpha^2}}{2}\right)$.
122166
Significance of $i$ in the Schrödinger equation
118586
Confused About Trigonometric Substitution
32489
How does bra-ket notation work?
33100
Trigonomnetric equality involving tg
55869
Use the Maclaurin series to prove that $e^{i\theta} = cos(\theta) + isin(\theta)$
73829
Coulomb's Law: why is $k = \dfrac{1}{4\pi\epsilon_0}$
67410
Why does this expected value simplify as shown?
79757
Why does the density matrix $\rho$ obey a wrong-signed Heisenberg equation of motion?
69854
Why is there a minus sign in this wave equation derivation?
56934
How do we prove $\cos(\pi/5) - \cos(2\pi/5) = 0.5$ ?.
106803
How to see $\cos x \leq \exp(-x^2/2)$ on $x \in [0,\pi/2]$?
122603
How does $\mathcal E(\rho)=\mathrm{Tr}_{env}[U(\rho\otimes\rho_{env})U^\dagger]$ turn into $P_0\rho P_0+P_1\rho P_1$?
109853
Laplace transform of $\cos(at)$
83532
Confusion I have regarding Einstein's 1905 derivation of LT
25569
Intuitive understanding of the derivatives of $\sin x$ and $\cos x$