User:GONE cosmos

Hello my friend! I am a student who lived in Beijing and welcome to my wiki MyPage in Chinese click here    $$\int\frac{\sqrt{x^2+1}}{x}{dx}$$ {| style="float: left; margin-right: 1em; margin-bottom: 0.5em; height: 385px; width: 490px;border: #C0C0C0 solid 1px;"