Primitive of Arctangent Function/Also presented as

Primitive of Arctangent Function: Also presented as
This result can also be presented as:
 * $\ds \int \arctan x \rd x = x \arctan x - \ln \sqrt {x^2 + 1} + C$

Proof
From Primitive of $\arccot x$:
 * $\ds \int \arctan x \rd x = x \arctan x - \frac {\map \ln {x^2 + 1} } 2 + C$

The result follows by observing:
 * $\dfrac 1 2 \log x = \log \sqrt x$

from Logarithm of Power.