Synonyms for Demonstrated:

adj.

•evidential (adjective)
evidential, counter-evidential, validated, Exhibited, supported, authentic, documented, substantiated, proven, witnessed, Exemplified, Vouched, corroborated, Testified, established, confirmed, certified.
•manifest (adjective)
observable, perceivable, palpable, embodied, viewable, corporeal, concrete, Manifested, Appeared, revealed, Displayed, Shown, discernible, visible, Exhibited, Materialized, tangible, present, proved, evidential, touchable, incarnate.

n.

•demonstrated (noun)
incontestable, incontestible.

v.

•ascertained (verb)
checked, ascertained, Audited, verified, assured, found out, double checked.
•demonstrated (verb)
uncovered, convinced, Flaunted, unveiled, exposed, unmasked, Flourished.
•evinced (verb)
documented, attested, Evinced, proved, Exemplified, Vouched, declared, Betokened, proven, corroborated, established, observed, illustrated, Testified, determined, witnessed, Adduced, stated, deposed, Connoted, Indicated, substantiated, supported, Exhibited, confirmed, validated, certified, Avouched, authenticated, Manifested.
•manifested (verb)
presented, showed.
•proved (verb)
confirmed, proved, certified, verified, established, ascertained, determined, proven.

Other synonyms:

•Other relevant words:
incontestable, incontestible.

Usage examples for demonstrated

1. That he has fully accomplished his purpose is demonstrated by the fact that it is now looked upon as the most standard and authentic history of Freemasonry in existence. – The Children of the World by Paul Heyse