In: Advanced Math
Let C(R) be the vector space of continuous functions from R to R with the usual addition and scalar multiplication. Determine if W is a subspace of C(R). Show algebraically and explain your answers thoroughly.
a. W = C^n(R) = { f ∈ C(R) | f has a continuous nth derivative}
b. W = {f ∈ C^2(R) | f''(x) + f(x) = 0}
c. W = {f ∈ C(R) | f(-x) = f(x)}.
a). { has a continuous nth derivative } .
Let , .
are continuous , where denotes nth derivative of .
Now , are also contiunuous as sum of two contunuous function are also continuous .
So W is closed under addition .
is also continuous
So W is closed under scalar multiplication .
Hence W is a subspace.
.
(b). { }
Let ,
Now ,
Also ,
So
Hence W is a subspace .
.
(c). { }
Let ,
Also
So W is closed under addition and salar multiplication . Hence W is subspace .