Inequality Definition and 1000 Threads

  1. E

    Magnitude of Complex Exponential Polynomial Inequality

    Homework Statement Digital filter analysis - this is just one part of a multi-part question I can't move forward with. It's supposed to be an auxilliary question and isn't the "meat" of the problem. Find b, such that maximum of the magnitude of the frequency response function...
  2. G

    Proving an Inequality: (1+a)q < q/(1-a) for a < 1 and Positive Real Numbers

    Hello to everyone. This is my first time here so I hope I will not cause any unwanted trouble. Straight to the problem. I have one inequality for which I would like to prove, but I do not know how. The inequality has the following form:- (1+a)q < q/(1-a), where a < 1 and q can be any positive...
  3. S

    Finding the domain for inequality

    Homework Statement The problem is: for all 0≤a≤1 so i need to find the domain Homework Equations N/A The Attempt at a Solution I tried it like this: yet my solution is wrong,i am not so sure why. wolfram gives me this;
  4. karush

    MHB Inequality with absolute value

    Write as one inequality with an absolute value x<-5 or 8<x not sure how you introduce the absolute value in this to solve it. thanks ahead
  5. T

    Triangle Inequality for a Metric

    Homework Statement Prove the triangle inequality for the following metric d d\big((x_1, x_2), (y_1, y_2)\big) = \begin{cases} |x_2| + |y_2| + |x_1 - y_1| & \text{if } x_1 \neq y_1 \\ |x_2 - y_2| & \text{if } x_1 = y_1 \end{cases}, where x_1, x_2, y_1, y_2 \in \mathbb{R}...
  6. Saladsamurai

    What Values of x Satisfy the Inequality \(\frac{x-1}{x+1} > 0\)?

    Homework Statement Find all x for which \frac{x-1}{x+1}>0 \qquad(1)Homework Equations (2) AB > 0 if A,B >0 OR A,B < 0 (3) 1/Z > 0 => Z > 0 The Attempt at a Solution Since (1) holds if: (x-1) > 0 \text{ and } (x+1) > 0 \qquad x\ne -1 then we must have x>1 AND x>-1 and since (1) also...
  7. Saladsamurai

    Solve Ineq. in Spivak Calculus 4(ii): 5-x2>8

    Homework Statement I am doing the HW in Spivak's calculus (problem 4 (ii) ) on inequalities. The problem statement is: find all x for which 5-x2 > 8The Attempt at a Solution I know this is a simple problem, but bear with me for a moment. I want someone who is familiar with Spivak to tell...
  8. T

    Using Triangle Inequality to find a magnitude

    Homework Statement Let a, x, and y be real numbers and let E > 0. Suppose that |x-a|< E and |y-a|< E. Use the Triangle Inequality to find an estimate for the magnitude |x-y|. Homework Equations The Triangle Inequality states that |a+b| <= |a| + |b| is valid for all real numbers a and...
  9. G

    Jensen inequality, unexplained distribution, very confusing problem

    Hi everyone I don't know if I can find someone here to help me understand this issue, but I'll try the jensen inequality can be found here http://en.wikipedia.org/wiki/Jensen%27s_inequality I have the following discrete random variable X with the following pmf: x 0...
  10. C

    MHB What is the proof for this polynomial inequality problem?

    I may have posted this back in the Old Country, but: let the polynomial: \[P(x)=x^n+a_1X^{n-1}+ ... + a_{n-1}x+1 \] have non-negative coeficients and \(n\) real roots. Prove that \(P(2)\ge 3^n \) CB
  11. P

    MHB How Can We Prove This Positive Real Number Inequality?

    Prove that for positive real numbers a,b (a+1/b+1)^(b+1) is greater than or equal to (a/b)^(b). The case in which a<b is easy to prove, but after trying to represent the inequality with an integral, I'm a bit stumped. Any ideas?
  12. S

    Proving Inequality: Solving for x in x+3^x<4

    Find all numbers x for wich: x+3^x<4 Relevant equations (PI) (Associative law for addition) (P2) (Existence of an additive identity) (P3) (Existence of additive inverses) (P4) (Commutative law for addition) (P5) (Associative law for multiplication) (P6) (Existence of a multiplicative identity)...
  13. H

    Matrix Inequality: Is BTB <= B1TB1?

    I am puzzled about this simple case, Suppose we have (A+B)T(A+B) <= (A+B1)T(A+B1), Can we say something about the relation between BTB and B1TB1? For example, is it correct if I say BTB <= B1TB1?
  14. A

    Strange proof of Young's inequality

    I'm trying to absorb a perplexing proof of Young's inequality I've found. Young's inequality states that if A,B \geq 0 and 0 \leq \theta \leq 1, then A^\theta B^{1-\theta} \leq \theta A + (1-\theta)B. The first step they take is the following: We can assume B \neq 0. (I get that.) But then...
  15. M

    Unraveling Inequality: Can We Bridge the Gap?

    The problem and my question and thoughts are all in the picture.
  16. J

    Prove Inequality: x,y,z - Solution Needed

    I found this problem the other day, seems interesting but I am still not sure about the solution Anybody can help x, y, z are numbers with x+y+z=1 and 0<x,y,z<1 prove that sqrt(xy/(z+xy))+sqrt(yz/(x+yz))+sqrt(xz/(y+xz))<=3/2 ("<=" means less or equal)
  17. E

    Hölder's inequality for sequences.

    Homework Statement Let 1\leq p,q that satisfy p+q=pq and x\in\ell_{p},\, y\in\ell_{q}. Then \begin{align} \sum_{k=1}^{\infty}\left\vert x_{k}y_{k}\right\vert\leq\left(\sum_{k=1}^{\infty}\left\vert x_{k}\right\vert^{p}\right)^{\frac{1}{p}}\left( \sum_{k=1}^{\infty}\left\vert...
  18. H

    Bell inequality experiments and photon polarisation issue

    I am confused by the role of photon polarisation in Bell inequality experiments. The original logic of EPR as I understand it is based on the HUP such that QM predicts that measurement of momentum on one particle should affect the measurement of position of the other particle. Yet across...
  19. M

    What is the source of my confusion about inequality?

    I posted the paragraph with the inequality where I am confused... I also added a portion i highlighted in red
  20. S

    Using the Cauchy-Schwarz inequality to prove all real values for a, b, and theta

    Homework Statement Use the Cauchy-Schwarz inequality to prove that for all real values of a, b, and theta (which ill denote as θ), (a cosθ + b sinθ)2 ≤ a2 + b2 Homework Equations so the Cauchy-Schwarz inequality is | < u,v>| ≤ ||u|| ||v|| The Attempt at a Solution I'm having...
  21. S

    How Does the Cauchy-Schwarz Inequality Prove a Vector Inequality?

    Homework Statement Let u = [a b] and v = [1 1]. Use the Cauchy-Schwarz inequality to show that (a+b/2)2 ≤ a2+b2/2. Those vectors are supposed to be in column form. Homework Equations |<u,v>| ≤||u|| ||v||, and the fact that inner product here is defined by dot product (so <u,v> = u\cdotv)...
  22. P

    Inequality 0<x<1: Is $\frac{x-1}{x}<ln(x)<x-1$ True?

    is \frac{x-1}{x}<ln(x)<x-1 valid for 0<x<1 I think it is I just want to get a second opinion.
  23. L

    Showing the inequality holds for an interval (?)

    Showing the inequality holds for an interval (?) Homework Statement Hi, my homework question is: Show that the inequality \sqrt{2+x}<2+\frac{x}{4} holds \forallx\in[-2,0] Homework Equations The Attempt at a Solution I tried using IVT or bisection method, but they are just for...
  24. I

    Distance between sets (a triangle-type inequality)

    I've been reading a book called Superfractals, and I'm having trouble with a particular proof: Definitions: The distance from a point x \in X to a set B \in \mathbb{H}(X) (where \mathbb{H}(X) is the space of nonempty compact subsets of X is: D_B(x):=\mbox{min}\lbrace d(x,b):b \in B\rbrace The...
  25. C

    Property of Natural Log- Inequality equation

    Hi. I just saw on wikipedia that natural logarithm has such a property: [x/(1+x)] < ln (1 + x) < x (http://en.wikipedia.org/wiki/Natural_logarithm) Can anyone pls tell me how to prove this? Proving [x/(1+x)] and ln (1 + x) less than 'x' is easy.. But how abt [x/(1+x)] < ln (1 + x)...
  26. S

    Inequality with Circle and Triangle in Euclidean Geometry

    Homework Statement Please see below... Homework Equations Please see below... The Attempt at a Solution Hi. This question is on geometry with circle and triangle. I am stuck only on 2 parts of the solution and not the whole solution... Thank you...
  27. A

    Solving Simple Inequality: Tips/Suggestions Needed

    Is there a way to do this without differentiation? \left(a+b\right)^{p} \leq a^{p}+b^{p} 0<p<1 and a,b\geq 0 pulling the a out of the the first part and dividing by it to get \left(1+\frac{b}{a}\right)^{p}\leq 1+\frac{b}{a}^{p} This seems like the way to go but am stuck. Any...
  28. S

    How can an inequality be manipulated to show a specific range of values?

    In an example in my textbook, it says the following: "If -1 ≤ x ≤ 1, then 0 ≤ x2 ≤ 1. " Can someone explain to me how to move from the first statement to the second statement please? I'm not quite sure how the -1 turned into a 0...
  29. M

    Prove this inequality with binomial

    Homework Statement Prove that \sum_{k=0}^n {3k\choose k}\ge \frac{5^n-1}{4}Homework Equations {3k\choose k}= \frac{(3k)!}{k!(2k)!}The Attempt at a Solution I tried using the induction principle, but... Here my attempt: For n=0 1>0 ok Suppose that is true for n, i.e.: \sum_{k=0}^n...
  30. S

    I need assiatance to understand a problem in Inequality

    Hello Friends, I at a loss to understand the parts of the following proof: For any positive ineteger n, prove that: (1+1/n)^n < (1+1/n+1)^n+1 a, b positive real numbers such that a < b Proof: b^n+1 - a^n+1 = (b-a)(b^n+ab^n-1+...+a^n) I could not understand the following part: By...
  31. J

    Help proving complex inequality

    This may seem trivial, but for some reason I am having trouble with it. For a and b in the complex plane, I am trying to prove the following: |a|^2+|b|^2 >= |(a+b)/2|^2 I need this for part of a larger proof.
  32. F

    Sequence inequality, epsilon N argument

    Homework Statement I already have the solutions, but I am not sure what the solutions are trying to say. http://img194.imageshack.us/img194/2595/unledlvc.jpg So in I don't understand this, we have n > \frac{1}{\epsilon} and If (and I am guessing we really want this to...
  33. H

    Precalc project: positive values in an inequality

    Homework Statement Determine the set of positive values of x that satisfy the following inequality: (1/x) - (1/(x-1)) > (1/(x-2)) a) (0, 1) union (2^1/2, 2) b) (0, 1/2) union (1, 2) c) (1/2, 1) union (2^1/2, 2(2^1/2)) d) (0, 2^1/2) union (3/2, 2) e) (1, 2^1/2) union (2, 2(2^1/2))...
  34. N

    Inequality from Stirling's formula

    In this link is a part of a book on approximations of functions. http://books.google.com/books/about/An_Introduction_to_the_Approximation_of.html?id=VTW2cmjC43YC I'd be thankful if someone would explain how the inequality near the top of page 17 was gotten.
  35. Z

    Probability: Markov's and Cheyshev's Inequality what in the world?

    Homework Statement So these were introduced in my lecture and I'm not really clear what they do or why it's true or when they're useful. Can you please explain them to me in a simple way? Thank you.Homework Equations Markov's Inequality: If X is a non-negative random variable, (that is, P(X...
  36. C

    Why Must the Expectation Value of Momentum Squared Be Strictly Positive?

    Homework Statement Why is \langle p^2\rangle >0 where p=-i\hbar{d\over dx}, (noting the ***strict*** inequality) for all normalized wavefunctions? I would have argued that because we can't have \psi=constant, but then I thought that we can normalize such a wavefunction by using periodic...
  37. G

    Complex inequality with absolute values

    Homework Statement Determine the values of z \in \mathbb{C} for which |z+2| > 1 + |z-2| holds. Homework Equations Nothing complicated I can think of. The Attempt at a Solution For real values this holds for anything greater than 1/2. If I could figure out the boundaries of the...
  38. W

    Can You Prove This Inequality for Positive Real Numbers a,b,c,d with Sum of 1?

    a,b,c,d\in\mathbb{R^{+}}\;\;,a+b+c+d=1. Then prove that \left( a+\dfrac{1}{b}\right).\left(b+\dfrac{1}{c}\right).\left(c+\dfrac{1}{a}\right)\geq \left(\dfrac{10}{3}\right)^3 Anyone an idea on how to start with this exercise?
  39. G

    Young's Inequality alternative proof

    Young's Inequality can be restated as: s^(x)t^(1-x)<=xs + (1-x)t where s,t>=0 and 0<x<1. Basically I've been asked to prove this. I've been fiddling about with it for a couple of hours to no avail. I've tried to substitute t=e^u and s=e^v and then use partial differentiation w.r.t to...
  40. H

    Triangle Inequality for integrals proof

    Homework Statement What I want to show is this: ∫|x+y| ≤ ∫|x| + ∫|y| Homework Equations |x+y| ≤ |x| + |y| The Attempt at a Solution So I thought if I used the triangle inequality I could get to something along the lines of: Lets g belong to the real numbers ∫|x+y| =...
  41. A

    Best bound for simple inequality

    Hello all, the problem I have is the following: Suppose f \in C^1(0,1) and f(0) = 0, then f^2(x) \le \int_0^1 f^2(x) dx, but I was wondering if 1 is the best constant for the inequality. In other words, how do I determine the best bound for f^2(x) \le K \int_0^1 f^2(x) dx...
  42. G

    Inequality of a complex number

    Homework Statement Suppose that w is a complex number which is not both real and \left\lfloorw\right\rfloor\geq1 (the absolute value of w). Verify that Re[(1-w^{2})^{1/2}+iw]>0. Homework Equations The Attempt at a Solution I attempted to solve this problem by dividing it into...
  43. N

    Solving Rational Inequalities: How to Determine the Interval of Solutions?

    Homework Statement 2x-1 _____ > 0 5x+3 Homework Equations The Attempt at a Solution Just wondering, my teacher taught us that youre only supposed to look at what makes the denominator = 0, and don't look at the numerator because it has no affect on anything. So, if i...
  44. H

    Is ((2x)3^x)/(x+1) < 0 Solvable for x?

    Can Someone please solve this inequality! Homework Statement ((2x)3^x)/(x+1) < 0 Thanks is advance! Homework Equations The Attempt at a Solution
  45. M

    A limsup inequality (showing that the root test is stronger than the ratio test)

    Homework Statement Show that if a_n > 0 for all n, \liminf{\frac{a_{n+1}}{a_n}} \leq \liminf{a_n^{1/n}} \leq \limsup{a_n^{1/n}} \leq \limsup{\frac{a_{n+1}}{a_n}}Homework Equations \liminf{a_n^{1/n}} \leq \limsup{a_n^{1/n}} \liminf{\frac{a_{n+1}}{a_n}} \leq \limsup{\frac{a_{n+1}}{a_n}} These...
  46. T

    Show that this inequality is true for all x, y ε R

    Homework Statement This is part of a question on absolute convergence on series. The following equation is given as a hint. It says that before answering the question on series I should prove that |xy| <= 1/2(|x|^2 + |y|^2) for any x,y ε R Homework Equations The Attempt at a...
  47. L

    Real Analysis problem (easy), Triangle inequality

    Homework Statement > a[1], a[2], a[3], .. , a[n] are arbitrary real numbers, prove that; abs(sum(a[i], i = 1 .. n)) <= sum(abs(a[i]), i = 1 .. n) Homework Equations The Attempt at a Solution I have uploaded my attempt as a pdf file, since I'm not too familiar with the...
  48. ElijahRockers

    PSAT abstract inequality question.

    p<q, r<s, and r<q. Which of the following statements must be true? I. p<s II. s<q III. r<p The correct answer could be either one statement, a combination of statements, or none of the statements. Came across this question while helping some high school students prepare for their SATs...
  49. W

    Solving Polynomial Inequalities Using Synthetic Division and the PQ Rule

    Homework Statement 4x5-16x4+9x3+23x2-15x-9 > 0 Homework Equations Synthetic division PQ Rule? The Attempt at a Solution Don't know how or where to begin
  50. K

    Can You Square an Inequality for Sin(x)?

    Hello I am doing a calculus proof with epsilon-delta and I am trying to say the following: -1\leqsin x\leq1 and now I want to get (sin x )^2 ...so can you just square all sides of the inequality like this: (-1)^2\leq(sin x)^2\leq(1)^2 ?? According to the rule for inequalities...
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