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**eigenspace** let me take a funtion that vanish at end points x=0 and x=L. do these functions qualify to be a vector space?

i proceeded this way - to show that they qualify, i have to show that they are closed, commutative etc. i think they are not closed. so they dont form vector space.am i correct??

What kind of functions? What is L? You must write questions more clearly and giving information

Tonio

how about periodic functions obeying f(0)=f(L)?(hints please)

and functions that obey f(0)=5?(hints please)

many thanks.