### Real Analysis : Open and closed discrete spaces

Show that every subset of a discrete space is both open and closed.

- Anthropology
- Art, Music, and Creative Writing
- Biology
- Business
- Chemistry
- Computer Science
- Drama, Film, and Mass Communication
- Earth Sciences
- Economics
- Education
- Engineering
- English Language and Literature
- Gender Studies
- Health Sciences
- History
- International Development
- Languages
- Law
- Mathematics
- Philosophy
- Physics
- Political Science
- Psychology
- Religious Studies
- Social Work
- Sociology
- Statistics

Show that every subset of a discrete space is both open and closed.

An open-top box is to be constructed from a 6 by 8 foot rectangular cardboard by cutting out equal squares at each corner and the folding up the flaps. Let x denote the length of each side of the square to be cut out. 1. Find the function V that represents the volume of the box in terms of x. 2. Graph this function and sh

Please help with the following problems on geometry and topology. Provide step by step calculations. See the attached files for diagrams to go along with the questions. Find the value of x and any unknown angles. Find the measure of one angle in the polygon. Round to nearest tenth if needed. 4. Regular 30-gon 5. Regular

A- find the measure of one angle in the polygon. round to nearest tenth if needed. 1- regular 30- gon 2- regular 35- gon b- sum of angle and number of sides to polygon sum of angles number of sides to polygon 5040 1800 2160 4140 c- tell whether the stateme

(a) Draw polygons with sides n = 4, 5, 6, 7, 8, 9, 10 for the following three cases. 1- non regular polygon 2- regular polygon 3- a shape that is not a polygon (b) Name the following polygons Number of sides name of polygon ------------------ -------------------- 4 5 6 7 8 9 10

Proof that f is continuous for each x in D in accordance with the epsilon-delta defitinition of continuity(can use the defintion involving f(x+h) (2 problems) f(x)=x/(x+1), D={x in R:x>-1} (can restrict |h|<(x+1)/2 f(x)=1/sqrt(x-4), D={x in R:x>4} (can restrict |h|<(x-4)/2

The volume of a cylinder (think about the volume of a can) is given by V = pi*r2h where r is the radius of the cylinder and h is the height of the cylinder. Suppose the volume of the can is 121 cubic centimeters. Write h as a function of r. b) What is the measurement of the height if the radius of the cylinder is 3 centimete

1) Using the graph, what is the value of x that will produce the maximum volume? 2) The volume of a cylinder (think about the volume of a can) is given by V = πr2h where r is the radius of the cylinder and h is the height of the cylinder. Suppose the volume of the can is 121 cubic centimeters. Write h as a function

An engineer's plan shows a canal with a trapezoidal cross section that is 8 ft deep and 14 ft across at the bottom with walls sloping outward at an angle of 45 degrees. The canal is 620 ft long. A contractor bidding for the job estimates the cost to excavate the canal at $1.75 per cu yd. If the contractor adds 10% profit, what s

A solid whose base is the ellipse (x^2/16)+ (y^2/9)= 1 has cross sections perpendicular to the base and parallel to the minor axis are semi-ellipses of height 5. Find the volume.

b. The volume of a cylinder(think about the volume of a can)is given by v=pir^2h where r is the radius of the cylinder and h is the height of the cylinder. Suppose the volume of the can is 100 cubic centimeters, what is the measurement of the height of the cylinder is 2 centimeters? show work c. Graph this function

What is the measurement of the height if the radius of the cylinder is 2 centimeters? Graph this function also The formula for calculating the amount of money returned for an initial deposit money into a bank or CD is given by A=P(1+r)^nt n A is the amt of

An open top box is to be constructed from a 6 by 8 foot rectangular cardboard by cutting out equal squares at each corner and then folding up the flaps. Let x denote the length of each side of the square to be cut out. Find the function V that represents the volume of the box in terms of x. Show and explain the answer, and a

Determine the structure of the homology group H_n(X), n >= 0, if X is (a) the set of rational numbers with their usual topology; (b) a countable, discrete set.

Creating ways to teach surface area and volume. I am especially interested in methods which will help students connect geometry to life in the real world.

John has 300 feet of lumber to frame a rectangular patio (the perimeter of a rectangle is 2 times length plus 2 time width) He wants to maximize the area of his patio (area of a rectangle is length times width). What should the dimensions of the patio be?

A farmer wishes to erect a striaght fence that will bisect the angle formed by two existing (straight) fences. Unfortunetly, the vertex of the angle is in the middle of a lake. How can we locate the fence line using straight edge and compass? Please see the attached file for the fully formatted problem.

The volume of a cube is given by V = s3. Find the length of a side of a cube if the Volume is 729 cm3.

John has 300 feet of lumber to frame a rectangular patio (the perimeter of a rectangle is 2 times length plus 2 times width). He wants to maximize the area of his patio (area of a rectangle is length times width). What should the dimensions of the patio be?

Please find the 1) length and 2) direction (when defined) of 1) A X B and 2) B X A Please show all work, including the grids for the determinants. Thank you. A = 2i - 2j - k B = i - k

Let X be Sierpinski space: X={x,y} with topology {X,empty set, {x}} . prove that X is contractible.

Is it possible to partition a unit square [0, 1] X [0, 1] into two disjoint connected subsets A and B such that A and B contain opposing corners? I.e., such that A contains (0, 0) and (1, 1), and B contains (1, 0) and (0, 1)? *----0 | | | | 0----* Evidently, A and B couldn't be path-connected because a path running fr

(See attached file for full problem description) --- Determine the structure of the homology group Hn(X), n  0, if X is (a) the set of rational numbers with their usual topology; (b) a countable, discrete set.

Assume X and Y are arcwise connected and locally arcwise connected, X is compact Hausdorff, and Y is Hausdorff. Let f: X-->Y be a local homeomorphism. Prove that (X,f) is a covering space.

Prove that a non-simple quadrilateral can be inscribed in a circle <=> opposite angles are equal (both directions).

A circular table measures about 0.9 m around its edge. What is the approximate length of its diameter.

1. Consider the graph of y = tan x. (a) How does it show that the tangent of 90 degrees is undefined? (b) What are other undefined x values? (c) What is the value of the tangent of angles that are close to 90 degrees (say 89.9 degrees and 90.01 degrees)? (d) How does the graph show this? 2. A nautical mile depends on l

The Brouwer Fixed-Point Theorem Let denote the closed unit ball in Euclidean space : . Any continuous map from onto itself has at least one fixed point, i.e. a point such that . Proof Suppose has no fixed points, i.e. for . Define a map , , by letting be the point of intersection of and the ra

Lemma. Let {Ui} be an open covering of the space X having the following properties: (a) There exists a point x0 such that x0Ui for all i. (b) Each Ui is simply connected. (c) If i≠j, then Ui Uj is arcwise connected. Then X is simply connected. Prove the lemma using the following approach: To prove that any loop f: I

1- Prove that if AF/FB = AF'/F'B where A, B, F, F' are collinear and distinct then F does not have to equal F' 2- Suppose that the sides AB, BC, CD and DA of a quadrilateral ABCD are cut by a line at the points A' B' C' D' respectively, show that AA'/A'B * BB'/B'C * CC'/C'D * DD'/D'A = +1