вызнава́тьвы́знать

Imperfective вызнава́ть (ongoing or repeatedly)

Perfective вы́знать (completed or one-time)

Very rarely used word (top 30,000)

1.
to find out, to ascertain, to discover(вызнава́ть)
Example:
Он пытался вызнавать их планы.
He tried to find out their plans.
2.
To fully know(вы́знать)
the prefix вы- here, indicates it's a completion.
Example:
Я вызнаю как произнести эта буква.
I fully know how to pronounce this letter.

Info: Don't use this word if you just want to say "I know", this would be more like "I fully know" "I know completely how to play this"

Past

	imperfective	perfective
ты	вызнава́й!	вы́знай!
вы	вызнава́йте!	вы́знайте!

Active present	вызнающий		inquiring, investigative, ascertaining, finding out, discovering
Active past	вызнававший	вы́знавший	who was finding out, who was ascertaining, who was investigating
Passive present	вызнаваемый		ascertainable, discoverable, detectable
Passive past		вы́знанный
Gerund present	вызнавая		while doing (present)
Gerund past	вызнавав вызнававши	вы́знав вызнавши	while doing (past)