1 Integration cheat sheet

Place keep common integrals for lookup. Constant of integration is assumed \(c\) and not shown to save space.

Integral anti derivative
\(\int \cos x\ dx\) \(\sin x\)
\(\int \sin x\ dx\) \(-\cos x\)
\(\int \tan x\ dx\) \(-\ln \left ( \cos x\right ) \)
\(\int \frac {1}{x^{2}+a}\ dx\) \(\frac {1}{\sqrt {a}}\arctan \left ( \frac {x}{\sqrt {a}}\right ) \)
\(\int \frac {1}{x^{2}-a}\ dx\) \(-\frac {1}{\sqrt {a}}\operatorname {arctanh}\left ( \frac {x}{\sqrt {a}}\right ) \)
\(\int \frac {1}{\sqrt {-x^{2}+a}}\ dx\) \(\arcsin \left ( \frac {x}{\sqrt {a}}\right ) \)
\(\int \frac {1}{\sqrt {x^{2}+a^{2}}}\ dx\) \(\operatorname {arcsinh}\left ( \frac {x}{\sqrt {a}}\right ) \)
\(\int \frac {1}{\cos x}dx=\int \sec xdx\) \(\ln \left ( \sec x+\tan x\right ) \)
\(\int \frac {1}{\sin x}dx=\int \csc xdx\) \(\ln \left ( \csc x-\cot x\right ) \)

Integration by part is \(\int udv=uv-\int vdu\). For \(u\) pick the one which when differentiating it repeatedly it vanishes. So given integrand say \(x^{2}\sin x\), use \(u=x^{2}\) and \(dv=\sin x\).

For partial fractions uses \(\frac {f\left ( x\right ) }{\left ( {}\right ) \left ( {}\right ) }=\frac {A}{\left ( {}\right ) }+\frac {B}{\left ( {}\right ) }\) and so on.  Then find \(A,B\) by setting \(x\) to different values.