Intuitive explanation of Euler's formula $e^{it}=\cos(t)+i\sin(t)$
114411
Simple Proof of the Euler Identity $\exp{i\theta}=\cos{\theta}+i\sin{\theta}$
87934
Deducing $\sin x + \cos x \ge 1$ from $(\sin x + \cos x)^2 = 1 + 2 \sin x \cos x$
92010
A mathematically illogical argument in the derivation of Hamilton's equation in Goldstein
114031
Show that $\sum_{n=0}^\infty r^n e^{i n \theta} = \frac{1- r\cos(\theta)+i r \sin(\theta)}{1+r^2-2r\cos(\theta)}$
92205
Does Euler formula work for complex $z$?
24929
Why did Euler use e to represent complex numbers?
83290
How is the value of $\pi$ ( Pi ) actually calculated?
60577
Understanding the intuition behind math
136961
Why does the complex equation $z=Ae^{it}+Be^{-it}$ represent an ellipse?
105177
Gosper's unusual formula connecting $e$ and $\pi$
35571
Euler Rotations in Ordinary Space
117583
Why does $\sum_{n=0}^\infty (\sin{\frac{1}{n}})(\sinh{\frac{1}{n}})(\cos n)$ converge
149589
Analogous results to Euler's theorem
17277
Why is Euler's Totient function always even?
149447
Proving $\sin (x)=\cos (90^\circ-x)$
40556
Why is $\sin(\alpha+\beta)=\sin\alpha\cos\beta+\sin\beta\cos\alpha$
37040
Prove reduction formula for $\int \cos^n (x)\sin^m (x) \, dx$