proof of $\arctan(x)=\frac{i}{2}(\ln(x+i)-\ln(x-i)-i\pi)$ without solving $\int\frac{1}{x^2+1}dx$
71796
Proving $\rm \frac i 2 \ln\frac {x+i}{x-i}=\arctan x$ .
71681
Asymptotic expansion of $u_{n + 1} = \frac12 \arctan(u_n)$
125735
How do I evaluate $\int_{1/3}^3 \frac{\arctan x}{x^2 - x + 1} \; dx$?
63474
Showing $\sum_{i = 1}^n\frac1{i(i+1)} = 1-\frac1{n+1}$ without induction?
96328
Proving $e^{i\pi} = -1$ without proving $e^{ix} = \cos x + i\sin x$
147410
ArcTan(2) a rational multiple of $\pi$?
9003
prove $\frac{1}{2}\mathbf{\nabla (u \cdot u) = u \times (\nabla \times u ) + (u \cdot \nabla)u}$ using index notation
46948
Definite integral $\int_{\frac{1}{a}}^a \frac{\arctan(x)}{x}$
33791
Is it generally true that $\arcsin \theta + \arccos \theta = \frac{\pi}{2}$?
142365
Use of substitution into the integral $\int_0^2 \frac{\arctan x}{x^2+2x+2}dx$
113080
Prove $\tan\big(\frac{\pi}{2} -\theta \big) = \cot \theta$
65562
Proving the inequality $\arctan\frac{\pi}{2}\ge1$
55259
ArcTan[z] and ArcTan[x,y], Restriction and Conversion
26109
Show that $\arctan(n)$ is irrational for all $n \in \mathbb{N}$
7500
$\arctan$ of a square root as a rational multiple of $\pi$
151462
Find $\int \limits_0^1 \int \limits_x^1 \arctan \bigg(\frac yx \bigg) \, \, \, dx \, \, dy$
5747
$\cos(\arcsin(x)) = \sqrt{1 - x^2}$. How?