@WeiZhong A few observations/suggestions about Approach0. 1) Given that the search is limited to Math.SE is it possible add an MSE tag as a search criterion? As a kind of exclusion rule? In that questions without a specified tag are automatically excluded from the search results? 2) I just noticed, yes, I'm slow :-), that for Approach0 search results it has a significant impact whether we specify a definite or an indefinite integral.
(cont'd) The handy pad always inserts a definite integral. Leaving the limits unspecified is an option, but doing so affects the search results. There was a duplicate that I found only after I edited out the empty limits from the URL.
