# Is $\int\,dx=\int1\,dx$?

I'm just wondering if $$\int\,\mathrm dx$$ can be written instead of $$\int1\,\mathrm dx$$.

This sometimes comes up while finding the integrating factor of a suitable differential equation, when the coefficient of $$y$$ is $$1$$ and the integrating factor is thus $$e^{\int1\,\mathrm dx}=e^x$$.

• Yes, usually the $1$ is omitted, just like when we write $x$ instead of $1x$. – user2825632 Sep 16 '16 at 21:33
• @user2825632 Thank you very much. Please post this as an answer. – Skeleton Bow Sep 16 '16 at 21:34

Yes, usually the $1$ is omitted, just like when we write $x$ instead of $1x$.