Suppose (X, dX) and (Y, dY ) are metric spaces. Define d : (X ×Y
)×(X...
Suppose (X, dX) and (Y, dY ) are metric spaces. Define d : (X ×Y
)×(X × Y ) → R by d((x, y),(a, b)) = dX(x, a) + dY (y, b). Prove d
is a metric on X × Y .
Let (X,dX),(Y,dY ) be metric spaces and f: X → Y be a continuous
bijection. Prove that if (X, dX ) is compact, then f is a
homeomorphism. (Hint: it might be convenient to use that a function
is continuous if and only if the inverse image of every open set is
open, if and only if the inverse image of every closed set is
closed).
Let (X, dX) and (Y, dY) be metric
spaces.Define the function
d : (X × Y ) × (X × Y ) → R
by
d ((x1, y1),
(x2,y2)) =
dx(x1,x2)+dy(y1,y2)
Prove that d is a metric on X × Y .
d^2y/dx^2 − dy/dx − 3/4 y = 0,
y(0) = 1, dy/dx(0) = 0,
Convert the initial value problem into a set of two coupled
first-order initial value problems
and find the exact solution to the differential equatiion
Euclidean metric) The metric
d
((
x
1
,x
2
)
,
(
y
1
,y
2
)) =
√
(
x
1
−
x
2
)
2
+ (
y
1
−
y
2
)
2
on
R
2
generates the standard (product) topology on
R
2
.
(Connected Spaces)
(a) Let <X, d> be a metric space and E ⊆ X. Show that E is
connected iff for all p, q ∈ E, there is a connected A ⊆ E with p,
q ∈ E.
b) Prove that every line segment between two points in R^k
is connected, that is Ep,q = {tp + (1 − t)q |
t ∈ [0, 1]} for any p not equal to q in R^k.
C). Prove that every convex subset...