Some Integral Formulas

$$\int\limits_a^b {\frac{{f(x)dx}}{{f(a + b - x) - f(x)}} = \frac{{b - a}}{2}}$$

(src: http://y2u.be/BfZObnTIsYk)

$$\int {{e^{ - (a + bt)}}} *\sin (wt + c) =\\  - \frac{{{e^{ - (a + bt)}}*\sin (wt + c + \arctan \frac{w}{b})}}{{\sqrt {{b^2} + {w^2}} }}$$