Prove that $\cos(z)$ and $\sin(z)$ are surjective over the complex numbers.
73047
Proving surjectivity of $\cos(z)$ and $\sin(z)$ and find all $z : \cos(z) \in \mathbb R$ and all $z: \sin(z) \in \mathbb R$
11711
Prove trigonometry identity for $\cos A+\cos B+\cos C$
73687
Powers of $i$ in Complex Numbers.
84420
When is $\sin(x) = \cos(x)$?
76049
Prove that if $a|b$ and $a|c$ then $a|(sb+tc)$ for all $s, t \in \mathbb{Z}$
24221
Complex numbers - minimum value proof
45991
Why $f\colon \mathbb{Z}_n^\times \to \mathbb{Z}_m^\times$ is surjective?
114822
Prove or disprove an inequality involving complex numbers
145104
$T:$ $\mathbb{C}$ $\to$ $\mathbb{C}$ by $T(z)=\lambda z + \mu \bar{z}$ for every $z \in \mathbb{C}$
21391
Proving Functions are Surjective
46701
Complex Number Proof Questions
35244
Prove $\sin^2\theta + \cos^2\theta = 1$
118299
Show that $(\mathbb{Z}[x]/(x^{n+1}))^{\times}\cong \mathbb{Z}/2\mathbb{Z}\times\Pi_{i=1}^n\mathbb{Z}$
65435
Ring of trigonometric functions with real coefficients
158524
Complex numbers $z$ such that $|z|= 1$
86454
How to prove $\cos\left(\pi\over7\right)-\cos\left({2\pi}\over7\right)+\cos\left({3\pi}\over7\right)=\cos\left({\pi}\over3 \right)$
88857
Prove that Gauss map on M is surjective