"Play with", it is the most common word group in our Math Method of Theoretical Physics class. Although physics is not math, Math is essential for Physics. And that couse told us, at least me, a style to play with math, altough sometimes.....it is something hard.
Question: \int_{0}^{\infinite} \frac{lnX}{1+x^3}=?
Answer: Just consider the contour from 0->infinite->large circle->infinite->lower side of +x->0
and use this integration \int\frac{(lnX)^2}{1+x^3}
Math means miracle if you know how to play with it.
