1) Essayistic 2) Expositive 3) Instructive 1) Expositive 2) Expository writing 3) Informative 4) Instructive 5) Of the nature of exposition 
• (a.) Pertaining to, or containing, exposition; serving to explain; explanatory; illustrative; exegetical.
Ex·pos'i·to·ry adjective Pertaining to, or containing, exposition; serving to explain; explanatory; illustrative; exegetical. « A glossary or expository index to the poetical writers.» Johnson. 
[adj] - serving to expound or set fourth
expositive adjective serving to expound or set forth; `clean expository writing`
of the nature of exposition; serving to expound, set forth, or explain: an expository essay; expository writing.
serving to expound or set forth[SAT terms] serving to expound or set forth[TEKS ELAR vocabulary] serving to expound or set forth