Primitive of Reciprocal of Root of x squared plus a squared/Mistake

Source Work

2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.):

Appendix $7$: Integrals

Mistake

$\ds \int \frac {\d x} {\sqrt {a^2 + x^2} } = \dfrac 1 a \tan^{-1} {\frac x a}$

Correction

This should read:

$\ds \int \frac {\d x} {a^2 + x^2} = \dfrac 1 a \tan^{-1} {\frac x a}$

Sources

• 2014: Christopher Clapham and James Nicholson: The Concise Oxford Dictionary of Mathematics (5th ed.) ... (previous) ... (next): Appendix $7$: Integrals