necessitate vs require

necessitate and require both are verbs.

Word	Noun	Adjective	Verb	Adverb
necessitate	No	No	Yes	No
require	No	No	Yes	No

As verbs, necessitate and require are synonyms defined as:

Other synonyms of necessitate include ask, call for, demand, involve, need, postulate, take.

necessitate (verb)	require (verb)
require as useful, just, or proper	make someone do something
cause to be a concomitant	consider obligatory; request and expect
	have need of
	require as useful, just, or proper