# Assuming combined with mathematical notation of Integrate

I am trying to write down the following expression

Integrate[Exp[-a/2/x]/x/(x + 1), {x, 0, b}, Assumptions -> a > 0 && b > 0]


using mathematical notation. I have tried

Assuming[b > 0 && a > 0, Subscript[\[Integral], 0]^b E^(-(a/(2 x)))/(x (x + 1)) \[DifferentialD]x]


and in picture

However, Mathematica returns Syntax: Incomplete expression; more input is needed.

Could you please give guidance what is wrong here? Thank you.

There is a syntax error with Subscript

Try

Assuming[b > 0 && a > 0, Integrate[Exp[-a/2/x]/x/(x + 1), {x, 0, b}]]
(*-E^(a/2) ExpIntegralEi[-((a (1 + b))/(2 b))]*)

• Thanks for the answer! However, that is not my question. The first line works fine. I am trying to rewrite it using nice notation. I think that my first line of code Integrate[Exp[-a/2/x]/x/(x + 1), {x, 0, b}, Assumptions -> a > 0 && b > 0] and the screenshot should be equivalent and the former evaluates fine but the latter does not evaluate. The Subscript line is just a copy-paste of the screenshot from the Mathematica editor; I did not enter that. What is wrong in the screenshot? Do I write the integral incorrectly? May 12, 2022 at 8:47
• According to Mathematica's manual on Integrate, Subscript should be used to enter $x_{min}$, the lower boundary of the integral, when using "nice notation" (my terminology). May 12, 2022 at 8:49
• @drumath Might be! I tried to evaluate your code line(cut&paste) and Mathematica gives an error May 12, 2022 at 9:18

I found the issue. The solution was in the examples section of Integrate. The syntax error is with the superscript ^ after \[Integral] in Subscript[\[Integral], 0]^b. Ctrl+% has to be used instead of Ctrl+^.

Correctly:

Assuming[b > 0 && a > 0, \!$$\*SubsuperscriptBox[\(\[Integral]$$, $$0$$, $$b$$]$$\*FractionBox[SuperscriptBox[\(E$$, $$-\*FractionBox[\(a$$, $$2 x$$]\)], $$x \((x + 1)$$\)] \[DifferentialD]x\)\)]


This looks long here but copying it back to the Mathematica editor results again in the nice picture posted in the question.