Inequalities Definition and 329 Threads

  1. L

    Critical point exponents inequalities - The Coopersmith inequolity

    The Coopersmith inequolity: T=T_c, H\rightarrow 0^+ I'm confused by few things. What means H\rightarrow 0^+? And what difference will be if H\rightarrow 0^-? And what means T=T_c if we can't measure T_c in experiments? Then there is relation M \sim H^{\frac{1}{\delta}} That means if I...
  2. azizlwl

    Is (a+b+c)2>0 the correct approach for proving a2+b2+c2>ab+bc+ca?

    Homework Statement a. Prove: If a≠b≠c are real numbers, then a2+b2+c2>ab+bc+ca b. Prove: If a>0, b>0and a≠b, then a/b+b/a>2 Homework Equations (real numbers)2>0 The Attempt at a Solution a. (a+b+c)2>0 a2+b2+c2>-2(ab+bc+ca) Try to prove -2(ab+bc+ca) > ab+bc+ca but not true, -2.4...
  3. C

    Use Binomial Theorem and appropriate inequalities to prove

    Use Binomial Theorem and appropriate inequalities to prove! Homework Statement Use Binomial Theorem and appropriate inequalities to prove 0<(1+1/n)^n<3 Homework Equations The Attempt at a Solution So I started by.. \sum ^{n}_{k=0} (n!/(n-k)! k!) a^{n-k}b^{k} = n!/(n-k)!k! (1)^{n-k}...
  4. A

    How to solve a system of linear inequalities with absolute magnitudes?

    Hi everybody, I'd love to pick your brains about a problem in (seemingly?) linear algebra I've run into, trying to find the most efficient algorithm for solving a set of linear inequalities involving absolute magnitudes. During my research I've run into a problem that involves solving a...
  5. H

    Prove a limit using inequalities

    Using the inequalities: \sin x \leq x \leq \tan x valid in a zero range, prove that: \displaystyle\lim_{x \to{0}}{\frac{x}{\sin x}}= 1 Thank you!
  6. X

    Does Multiplying or Dividing by a Negative Number Change the Inequality Symbol?

    When we multiply or divide by a negative number a inequality of the type ≤, the symbol will become ≥, or >? -2x≥-4y, will become x ≤ 2y, or x < 2y?
  7. T

    Understanding Inequalities in Math: Solving Homework Problem Q7 iii

    Hi everyone. I am having a problem trying to understand the solutions of a homework problem that I had. Really need some help! Basically, I am trying to establish an inequality on kT using a given set of inequalities to work with. we have L \leq Q \leq H L \leq Q < Q+R_{1} \leq H and L...
  8. A

    What is the topic full of inequalities of 1/(n+1) and integrals?

    Have you ever see any books discussing these problems? I don't know the name of these topic.
  9. F

    MHB Equation with two inequalities

    This is part of a larger problem and I'm trying to solve 2h+1≤n≤2h+1 for h. If the equation had two equals signs or one inequality I think I could do it but I'm not sure how to proceed with both. In other words, I don't know how to manipulate an expression of the form (expr1)≤(expr2)≤(expr3)...
  10. Saladsamurai

    Inequalities and Absolue Values: Problem Solving Approach

    Hello all! :smile: In my quest to re-teach myself the basics of mathematics in a more rigorous fashion, I have found out that inequalities and absolute values are a weak point if mine. So I am working to address that. I am getting much better at it (with help from PF), but I have recently...
  11. V

    (Tricky) Absolute Value Inequalities

    Hello everyone, I'm posting here since I'm only having trouble with an intermediate step in proving that \sqrt{x} \text{ is uniformly continuous on } [0, \infty] . By definition, |x - x_0| < ε^2 \Longleftrightarrow -ε^2 < x - x_0 < ε^2 \Longleftrightarrow -ε^2 + x_0 < x < ε^2 + x_0 1...
  12. Saladsamurai

    Proofs: Absolute Values and Inequalities

    Homework Statement I am wondering if the general approach to these proofs involving absolute values and inequalities is to do them case-wise? Is that the typical approach (unless pf course you see some 'trick')? For example, I have: Prove that if |x-xo| < ε/2 and Prove that if |y-yo| <...
  13. E

    Use a graph to show the region defined by these 2 inequalities

    Homework Statement Use a sketch graph to show the region defined by y<2 and y>x The Attempt at a Solution y<2 is easy as its anything below y=2... but I am totally stuck on y>x.. How can I know what y is if i don't know what x is?? thanks for any help
  14. D

    How can we prove that \frac{x-1}{x-2} < 1 for x < 0?

    Homework Statement I just want to show that given x<0, \frac{x-1}{x-2} <1. The Attempt at a Solution I don't know why I am having trouble with this! I feel like this is so easy! So if x<0, then we know x-1<-1, x-2<-2 . So \frac{-1}{2}<\frac{1}{x-2} and...
  15. U

    Testing inequalities on intervals

    How do you see if the following inequality holds true for (-2,0)? (-x/4)*(x+2)>1 For that matter how do you test inequalities for a given interval in general? Certainly there must be a way other than to check all values of (-x/4)*(x+2) in (-2,0) and see if they are greater than 1?
  16. D

    Solving Inequalities with c and n: How-To Guide

    Homework Statement 4. Give a c > 0 and an integer n0 ≥ 1 such that, for all n ≥ n0. b. 16n log (n²) ≤ cn² The answer (from the sheet) is c = 32 Homework Equations ..The Attempt at a Solution When I attempt to solve such an equation I start at n=1, then go to n=2. but that way I get the...
  17. T

    How Do Different Metrics Compare in Multidimensional Space?

    Homework Statement (a) Show that for x,y\in \mathbb{R}^N: (i) d_{\infty} (x,y) \leq d_1 (x,y) \leq N d_{\infty} (x,y) ; (ii) d_{\infty} (x,y) \leq d_2 (x,y) \leq \sqrt{N} d_{\infty} (x,y). (b) Find constants A and B such that A d_1 (x,y) \leq d_2 (x,y) \leq B d_1 (x,y). Homework...
  18. O

    Proof by Induction - Inequalities

    Homework Statement Prove by induction that: (Please see attachment) Homework Equations The Attempt at a Solution Can someone please confirm if I have worked the question out correctly. Many thanks.
  19. T

    Help with writing a simple proof on inequalities

    1. Let m, n, p, q \in Z If 0 < m < n and 0< p \leq q, then mp < nq 2. Propositions/axioms I can use that relate to inequalities 2.4 Let m,n,p \in Z. If m < n and n < p, then m < p 2.5 For each n \in N there exists an m \in N such that m > n 2.6 Let m,n \in Z. If m \leq n \leq m then...
  20. L

    Solving trigonometric inequalities

    Hello, I am struggling with solving trigonometric inequalities. For example, solve: cos(\frac{\pi t}{3}) < \frac{1}{2}, 0<t<50 I wonder if one of these solutions is true: 1/ \frac{\pi}{3} + k2\pi < \frac{\pi t}{3} < \frac{5\pi}{3} + k2\pi, k \in Z 2/ \frac{\pi}{3} + 6k < \frac{\pi...
  21. W

    Inequalities involving division of two absolute values

    Homework Statement How to solve x for these inequality? Homework Equations |x-2|/|x+3|> (x+2) / (x+1) The Attempt at a Solution (x - 2)/(x + 3) > (x + 2) / ( x+1) the left side holds the condition that is x >= 2 however, I wonder the next step. should I crossly multiply so...
  22. Z

    Linear Programming double inequalities

    Homework Statement Find the dual of -d \leq Ax-b \leq d x \geq 0; c \cdot x = min where A is mxn matrix and x,d,b \in \mathbb{R}^n Homework Equations dual of canonical is of the form maximize b \cdot y A^{T}y \leq where y \in \mathbb{R}^m The Attempt at a Solution I tried...
  23. Saladsamurai

    Inequalities: I am apparently bad with them

    Hello folks :smile: I always thought that inequalities could be treated exactly like equations but somehow I seem to be loosing information or something. For example, if I wish to find all values of x for which the following is true: 1/x + 1/(1-x) > 0 I would 'solve' it as follows 1...
  24. N

    Can Limits on Variable a Be Determined Solely by p and q?

    Hi all, Given... a + b > p b > q Is there no way to place any limits on a in terms of p and q only? I know that one is allowed to add inequalities together but not subtract, but is there any other tricks one can play to solve this? Thanks, Natski
  25. C

    How can I solve inequalities involving absolute values?

    Homework Statement d) Show that \left|x-y\right| \leq \left|x\right|+\left|y\right| e) Show that \left|x\right|-\left|y\right| \leq \left|x-y\right| The Attempt at a Solution For item d) I've tried some approaches but none was promising. For item e), I tried squaring...
  26. J

    Solving Tricky Inequalities: Help with a Non-Factorable Numerator

    Inequalities- tricky question! hiii, i was wondering if anybody knew how to help me with this one tricky homework question. i can do most of the inequaliies I've come across, but how do you solve an inequality if you can't factor it? the question is: (x^2-4x+7)/(x^2+x-6) i know that the...
  27. N

    Match the inequalities with the corresponding statements.

    Homework Statement PROBLEM: Match the inequalities with the corresponding statements. INEQUALITIES: 1) |a-5|< 1/3 2) |a- 1/3|< 5 STATEMENTS: a) The distance from a to 5 is less than 1/3 b) a is less than 5 units from 1/3 The Attempt at a...
  28. N

    Precal, Inequalities involving absolute value

    Homework Statement DIRECTIONS: Express the intercal in terms of an inequality involving absolute value. PROBLEM: (-4, 4) MY STEPS: 1: (-4, 4) 2: -4<x<4 3: |x|< 4 MY ANSWER Is that correct? Is step 3 correct? The only reason that I included that part is becuase it says...
  29. S

    Do we have any proof of entanglement other than bells inequalities?

    do we have any proof of entanglement other than Bells Inequalities?bell's inequalities says that: - no physical theory of local hidden variables can reproduce all of the predictions of quantum mechanics or in other words - the correlations in/during Quantum Entanglement (QE) are stronger...
  30. nukeman

    Polynomial Inequalities - Finding the solution set?

    Polynomial Inequalities - Finding the solution set?? Homework Statement Solve the Inequality 2x^3 >-8x^2 Homework Equations The Attempt at a Solution Ok I am able to solve this by first figuring out the zeroes, and then testing with regions, So my answer is x=0 and x =...
  31. N

    Complex Number Inequalities: Sketching Solutions

    Hey guys, Just having a bit of trouble with inequalities. Homework Statement Sketch all complex numbers 'z' which satisfy the given condition: |z + i + 1| \leq |z - i| Homework Equations --- The Attempt at a Solution z + i + 1\leq z - i z + 2i + 1\leq z 2i + 1\leq...
  32. A

    Proving d, e and f as Linear Combinations of a, b and c

    Homework Statement Given: a>=b>=c>=0, d>=e>=f>=0, a>=d a+b>=d+e a+b+c=d+e+f a,b,c,d,e,f belong to Real numbers Prove that d, e, f can be expressed as linear combinations of a, b and c in such way: d=(c1+c2)*a+(c3+c4)*b+(c5+c6)*c e = (c1+c6)*a+(c2+c4)*b+(c3+c5)*c...
  33. Saitama

    Need help solving a Logarithmic Inequality?

    Got a load of Logarithmic Inequalities questions. Solved almost all of them but got stuck in a question. here's the question:- log3 |3-4x| > 2 Please help.
  34. W

    How Do Absolute Value Inequalities Apply to Different Sign Scenarios?

    Homework Statement I was trying to show that 1) |a+b|≤|a|+|b| 2) |a+b|≥|a|-|b| and find out how they were true when a,b>0, a,b<0, and a>0,b<0 Homework Equations 1) |a+b|≤|a|+|b| 2) |a+b|≥|a|-|b| The Attempt at a Solution For |a+b|≤|a|+|b| a,b>0 I got that |a+b|=a+b...
  35. P

    Why Does the Inequality 3x2 + 13 < 12x Have No Real Solution?

    Hi, Prove that the inequality 3x2 + 13 < 12x has no real solution Is it because: 3x2 - 12x + 13 < 0 And, using the quadratic equation we have to square root a negative number, meaning, the answer will be always greater than 0, not smaller? Thanks, Peter G.
  36. W

    Looking for descriptive material about log inequalities.

    So, I have this book that doesn't explain why you have to first find the domain, consolidate logs, solve the function as a rational inequality, find the key numbers, then find which numbers of the key numbers are actually in the domain according to the inequality, and finally write out the...
  37. S

    Simple inequalities question I promise

    (x+2)/(x+4) greater or equal to 1. I got two different answers here. X is greater than 4. Or a interval notation (-Infinite, 4) - which doesn't make sense but wouldn't the correct answer just be X is greater than 4? which would mean (4, infinite)? Homework Equations...
  38. R

    So, the statement is still true.

    I've been playing around with some proofs and find myself relearning how I do my mathmatical thinking. Just a general question regarding how to handle something like this. 0<a<b So a and b must be positive a/2 <b I just divided one side by two instead of "dividing through" like you...
  39. M

    How Can You Correctly Manipulate Inequalities Involving 1/(n-2) and Epsilon?

    so I have 1/(n-2). I have that n>max(epsilon+2,1). I need to get 1/(n-2) < epsilon. I know that 1/(n-2)<1/(epsilon+2-2)=1/epsilon. but 1/epsilon is not always less than epsilon. can you see any errors?
  40. E

    Zero to equations and inequalities

    Hello my question is why do we set some equations and inequalities to 0, for example quadratic equations/inequalities. I know that they should be 0, but why. How did people come with this when they invented it.
  41. T

    Does x<=b Imply max(x)=b and How Do Set Operations Differ?

    If x<=b does this mean max(x)=b? is x<=b equivalent to the interval (-infinity, b]?
  42. T

    Integral Calculus inequalities problem

    Homework Statement Hey, just wondering how I might go about doing this problem, as I really have very little idea... Prove the following inequality: \frac{1}{e}\leq\frac{1}{4\pi^{2}}\int_{R}e^{cos(x-y)}dxdy\leqe (hopefully this reads "one over e is less than or equal to one over four pi...
  43. J

    Does applying arccos() to both sides of an inequality preserve its relation?

    Please help me to confirm, weather the following step is correct |\gamma| \leq \cos (\beta) \arccos (|\gamma|) \leq \beta does taking the arccos() on both sides of equation changes the relational operator??
  44. E

    Analysis questions involving inequalities

    Homework Statement Prove that -1< x < 0 implies |x^2 - 2x +1| < 1.25|x-1| The Attempt at a Solution Attempt at 1st question: |(x-1)(x^2 + x -1)| < 1.25|x-1| |(x^2 + x -1)| < 1.25 -1.25 < (x^2 + x -1) < 1.25 -0.25 < x^2 + x < 2.25 -0.5 < (x + 0.5)^2 < 2.25 ** this leads to 0 < (x...
  45. S

    Relationship between inequalities in proofs

    Hi, Could you clarify the relationship between proofs that use ≤ and those that use <? For example, if it's already proven that "abs(b) ≤ a if and only if -a≤ b≤a" can we say this implies that "abs(b) < a if and only if -a< b<a"? It seems that since the first statement holds for all abs(b)...
  46. D

    Intersection of inequalities problem.

    I need to graph/find numbers for S∩T where S is x^2+y^2 <=100 and T is x+y<=14. I know I can find them simply by choosing/picking them, but are there any other solution ? I thought maybe doing x^2+y^2 <=100 + x+y<=14 = x^2+y^2 + x+y<=14 +100 = x^2+y^2 + x+y<=114 = x^2+y^2 <=...
  47. Y

    Another for Leggett inequalities.

    New J. Phys. 12 123007, 2010. Violation of Leggett inequalities in orbital angular momentum subspaces. We report an experimental test of Leggett's non-local hidden variable theory in an orbital angular momentum (OAM) state space of light. We show that the correlations we observe are in...
  48. Z

    Solving Inequalities: h(t) > 25

    Homework Statement I have a function h(t) = 30t - 5t^2. I need to find the interval for which h is > 25. Homework Equations The Attempt at a Solution h(t) = 30t - 5t2 - 25 > 0 -5(t2 - 6t + 5) > 0 iff t2 - 6t + 5 > 0 Then the answer is t > 5 and t < 1. But it is actually...
  49. G

    Finding the Range of x Values for Quadratic Inequalities

    Ive got a few questions id like checking please but i start with the one I got no clue about :S 1)Slove the equation x(x-2)=2-x So i asumme i slove it to zero, x^2-x-2=0 B)Use the solution to part A and the illustrated grapg to write down the solutions of I) X(x-2)<2-x II)X(x-2)>0...
  50. S

    Is Adding Zero Valid in Inequality Proofs?

    Hi I'm doing the first chapter of Spivak's Calculus and just a little concerned about a particular thing he does in the chapter. He is talking about the trichotomy axiom and that if a > b then a - b, this can be understood as expressing (a - b) > 0 and then the axiom can be interpreted...
Back
Top