Primitive of Root of x squared minus a squared/Inverse Hyperbolic Cosine Form/Mistake

Source Work

 * Table 2 Integrals

Mistake

 * $\ds \int \sqrt {x^2 - a^2} \rd x = \frac 1 2 a^2 \cosh^{-1} \frac x a + \frac 1 2 {x \sqrt {x^2 - a^2} } + C$

Correction
Should be:


 * $\ds \int \sqrt {x^2 - a^2} \rd x = \frac {x \sqrt {x^2 - a^2} } 2 - \frac {a^2} 2 \cosh^{-1} \frac x a + C$