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

Examples of Use of Primitive of $\dfrac 1 {\sqrt {x^2 + a^2} }$

Primitive of $\dfrac 1 {\sqrt {16 + 9 x^2} }$

$\ds \int \dfrac 1 {\sqrt {16 + 9 x^2} } = \dfrac 1 3 \map \ln {3 x + \sqrt {9 x^2 + 16} }$