On checking I see that the few www hits are either from this entry or from matches with other expressions.

Comments on deletion in previous post.

sankoku example sentence for 究める・窮める (but not 極める) 「学をー・真理をー」. 

学	23638546


学を究め	582	47.8%
学を極め	579	47.6%
学をきわめ	56	4.6%
学を窮め	0	0.0%

学問を究め	775	74.3%
学問を極め	236	22.6%
学問をきわめ	32	3.1%


真理を究め	339	67.5%
真理を極め	63	12.5%
真理をきわめ	58	11.6%
真理を窮め	42	8.4%

数学を極め	252	57.7%
数学を究め	185	42.3%

趣味を極め	1402	89.0%
趣味を究め	144	9.1%
趣味をきわめ	30	1.9%

Should be deleted, but submitting this to preserve diffs just in case it isn't.

Current conversation on 趣味を極める would seem to justify deletion. (学＝23638546、学を究める＝ 〜1000). Not evidently in a 国語辞典, except as an example. (I am fine with deletion, it's consistent, in spite of comments below).

===

The reason I ended up trying to enter 趣味を極める is not because of 趣味, but because because of *this* entry.  

First question was "how do I use 学を極める in a sentence" to mean "to study exhaustively". (I don't think you can)
Second question was "wait, is that kanji correct?" (no, it is not, or at least 究 or 極 would be much better)
Third question "can I 極める any　〇〇学" (answer: yes)
Fourth question "can I 極める something else, like, say, a 趣味" (picked this out of a hat. answer is: yes, and this usage is more common than any 〇〇学 I could find).

So I figured I'd start with the 趣味を極める, because it seemed like 極める could benefit from some clear transitive examples given the enormous number of glosses.  And, since this *one* example does not seem to be a particularly good one.  I then though I might suggest replacing this entry with the more readily-understandable, like the still-not-overly-common:
学問を極める: to (seriously) pursue an academic subject (eg. at a university).

But anyway, I am alright with all of it being deleted :)

@@ -4,0 +5,6 @@
+<keb>学を極める</keb>
+</k_ele>
+<k_ele>
+<keb>学を究める</keb>
+</k_ele>
+<k_ele>
@@ -5,0 +12 @@
+<ke_inf>&sK;</ke_inf>
@@ -13 +20 @@
-<gloss>to study exhaustively</gloss>
+<gloss>to pursue learning (in depth)</gloss>

Added additional PoS via batch update.Added additional PoS via batch update.
-*- via bulkupd.py -*-

@@ -12,0 +12,1 @@
+<pos>&v1;</pos>