Difference between Unknown and Unbeknownst

UNKNOWN vs UNBEKNOWNST: NOUN

A variable whose values are solutions of an equation
An unknown and unexplored region
Anyone who does not belong in the environment in which they are found
A person of no identity; a nonentity
That which is unknown.
Something that is not known.
A person who is not well known, as to the general public.
An unknown person, especially an Unknown Soldier.
A quantity of unknown numerical value.
A variable (usually x, y or z) whose value is to be found.
One who or that which is unknown.
Any fact or place about which nothing is known (as in the phrase "into the unknown").

Not known; not become an object of knowledge; not recognized, discovered, or found out.
Unknown in this sense is often used in the predicate, followed by to: as, a man unknown to fame; a fact unknown to the public. In this use it is also often used absolntely: as, unknown to me (elliptically for it being unknown to me), he made a new contract.
Not ascertained, with relation to extent, degree, quantity, or the like; hence, incalculable; inexpressible; immense.
Not to be made known, expressed, or communicated.
Not having had sexual commerce.

Unsung, Unbeknownst, Unsuspected, Nameless, Unnamed, Unfamiliar, Uncharted, Anonymous, Unexplored, Unmapped, Obscure, Undiscovered, Unknowable, Unidentified, Unknown quantity

Mysteriously, Supposedly, Presumably, Apparently, Secretly, Unwillingly, Inadvertently, Unwittingly, Surreptitiously, Double blind, Blind, Unwitting, Unknowingly, Unknown, Unbeknown

Unsung, Unbeknownst, Unsuspected, Nameless, Unnamed, Unfamiliar, Uncharted, Anonymous, Unexplored, Unmapped, Obscure, Undiscovered, Unknowable, Unidentified, Unknown quantity

Ostensibly, Covertly, Mysteriously, Apparently, Secretly, Unwillingly, Inadvertently, Unwittingly, Surreptitiously, Double blind, Blind, Unwitting, Unknowingly, Unknown, Unbeknown

In the previous example we found an unknown side but we can also use the Law of Sines to find an unknown angle.
Unknown If yes go to page two of application if yes or unknown staff needs to attach routing slip.
Administrative Issues Unknown Scoring Time required: unknown Clinical Utility The general information obtainable on the procedure suggests that the concept and practices have merit.
Tomb of the Unknown Warrior was born, other countries began to honor their unknown dead with symbolic tombs of their own.
Chemical preservatives should never be added to unknown or untreated liquid wastes and to samples of unknown matrix or source.
The treatment of unknown types has not changed: the unknown types are treated as binary.
Take an unknown solid from your assistants and please DO NOT forget to write your unknown number in your lab reports.
Pinho is out of commission due to an unknown injury, and it is unknown how long he will be debilitated.
The proportions of men with unknown numbers of sexual partners or unknown HIV status were underrepresented in both samples.
Currently Unknown IDEM Currently unknown due to the need for future dredge funding.

Unbeknownst to Paul, Emperor Nero had gone completely crazy.
Child pornography: Software files downloaded unbeknownst to the defendant.
Unbeknownst to him, much of the property contained wetland.
Unbeknownst to me I was already 6 weeks pregnant.
Unbeknownst to Blake, Faruk was now working for Alexis.
Marcos being planned and conducted unbeknownst to the public.
Palace site but unbeknownst to me was redirected.
Unbeknownst to Strothers, Koubek already marked her tardy.
Unbeknownst to her, the two are actually royalty.
Unbeknownst to many, and especially unbeknownst to me, there is a JB Arts Fest, and they've had it for ten years.