Inequalities Definition and 329 Threads

  1. P

    Solve Inequalities algebraically

    Homework Statement The Attempt at a Solution So when I started this question, I knew that 2r +3 > 0 in order for this whole thing to work so r > -3/2, and I know that if the middle term has to be more than 0, than only one more of the others is going to be negative, for the first...
  2. V

    Solving inequalities with rational expressions.

    Homework Statement Identify the solution set of the inequality. Homework Equations 5x + 1 / x- 1 ≥ 7 The Attempt at a Solution I multiplied both sides by x - 1 which gave me 5x+1 ≥ 7x - 7 Then I combined like terms together which gave me 8 ≥ 2x I divided both sides by 2 which gave...
  3. M

    Quadratic inequalities for complex variables?

    Hello, I was looking at Riley's solution manual for this specific problem. Along the way, he ended up with a quadratic inequality: If you looked at the image, he said it is given that λ is real, but he asserted that λ has no real roots because of the inequality. Doesn't that mean λ is...
  4. P

    What Is the Minimum Upper Bound of P(X>=5) Given -10<=X<=10 and E(X)=2?

    the random value X has the inequality , -10<=X<=10 and E(X)=2, what is the minimum upper bound of the probability P(X>=5) ? my first thought was to find this P(X>=t)<=E(X)/t which is 2/5 from Markov but its not correct, any ideas?
  5. S

    Can you explain the inequalities in exponential functions?

    Hello, could somebody please explain to me how 1-exp(-μt) ≤ μt and similarly (1-exp(-μt))exp(-λt) ≥ μt-μ2t2\2)(1-λt) Thanks a lot
  6. A

    Can the System of Inequalities in R be Solved with Real Numbers x, y, and z?

    Homework Statement x y and z are real numbers solve in lR (1+4x^2)y=4z^2 (1+4y^2)z=4x^2 (1+4z^2)x=4y^22. The attempt at a solution (1+4x^2)y(1+4y^2)z(1+4z^2)x=64x^2y^2z^2(x and y and z =/=0) (\frac{1}{4}+x^2)(\frac{1}{4}+y^2)(\frac{1}{4}+z^2)=xyz now i can tell from this that...
  7. S

    Solving inequalities algebraically, when root is 0

    Homework Statement Solve each inequality without graphing the corresponding function. State the solution algebraically and graph on a number line: x/x2-9≤0 so i factor out the denominator and get (x+3)(x-3) the root here is zero, but for some reason in the chart (for rational/reciprocal...
  8. S

    MHB Logic problem with arithmetic and inequalities

    Given: 1)it is not true that : 2>0 and 2+3 =7 2)if it is not true that 2>0 then 2 is less or equal to zero 3)if 2+3 =7 ,then 3+3 =8 4) but 3+3 is not equal to 8 Then prove: 2 is less or equal to zero
  9. S

    Understanding Inequalities: Part II Question | Need Help?

    I need help with the second part, I've managed to get through all of the part (i), but I have no idea where to really start with part (ii), any hints to start me off and I'll keep posting how I'm doing. thanks
  10. icystrike

    Inclusion-Exclusion Principle (Probability) - Bonferroni inequalities

    Homework Statement Hi PF! I am studying from a book - A first course in probability by Sheldon Ross, and I have came across this section whereby the are trying to prove the upper bound (equations 4.1 and 4.3) and lower bound (equation 4.2) of the inclusion-exclusion principle from basic...
  11. T

    Hello Could you me demostrate some integral inequalities?

    So could you please help me demonstrate some inequalities? Please! They want to prove them without calculating the integral. 1/3<=integral from 4 to 7 (x−3)/(x+5)dx<=1Thanks!
  12. E

    Question related to inequalities and limits that go to infinity

    I want to show that if f(x) > g(x) \forall x \in (-\infty, \infty) and \displaystyle\lim_{x\to\infty}g(x)=\infty , then \displaystyle \lim_{x\to\infty}f(x)=\infty . This result is true, correct? If so, what theorem should I use or reference to show this result? I wasn't sure if...
  13. E

    Solving algebraic inequalities

    Homework Statement Solve the following inequalities. Do each one algebraically then check your answers using your calculator's ability (Casio Classspad 330) to solve the inequalities and/or by viewing a suitable graph on your calculator. Homework Equations SEE IMAGE The Attempt at a...
  14. C

    Inequalities With Parity-Specific Domains

    When I was working on a rather difficult real-life math problem, I nearly found the solution. What I came up with was two inequalities: ##X≥\frac{2b-2}{2a+1}-1## and ##Y≥\frac{2b}{2a+1}-2## and the fact that ##X>Y##. However, ##X## must be an even integer and ##Y## must be an odd integer. Is...
  15. bohm2

    What do violations of Bell's inequalities tell us about nature?

    Please vote and if possible state the reasons for holding your belief. As a review here are the two major views with quotes by leading physicists in quantum foundations: 1. Observed violations of Bell's inequalities implies that nature is non-local: 2. Observed violations of Bell's...
  16. E

    Solving Inequalities: Tips & Tricks for Beginners

    Hi, I used to do all this type of inequalities but I have not practice this for almost a year and I have totally forgotten and didn't know why did the sign change. For example: If it's 3x ≤ 9 The answer: x ≥ 3 Is this right? I have actually forgotten in what circumstances we are suppose...
  17. C

    How Do You Solve the Inequality 4x^4 + (√2y)^4 ≤ 64 with Respect to x?

    Homework Statement Hi, i have a question regarding inequalities: I have to solve this inequality: 4x^4 +(√2y)^4 ≤64 My first first quess was to cancel out the square root (√2y)^2*(√2y)^2 4x^4 + 4y^2 ≤64 Then take the square root on both sides (here my question is: do you take one...
  18. JK423

    Why are Bell's inequalities violated?

    Hello guys, I am trying hard to understand the reason of the violation, and i hope you give me some help. Here is my understanding so far: Bell's inequalities are based on the measurement of non-commuting quantum observables, e.g. the measurement of the spin in x and z direction. This, to...
  19. T

    Inequalities with two different fractions which include x in the denominator.

    Homework Statement (x-2)/(x+3) less than (x+1)/(x) The Attempt at a Solution I broke it up into cases. When x+3 less than 0 and x less than 0 and then when both are positive, when one is positive and the other is negative and then the other way around. I'm not sure if that's the right way...
  20. P

    MHB Proving inequalities using calculus

    This might sound an odd/inappropriate request, but could someone post some inequalities that can be proven using calculus?
  21. C

    MHB Solving Inequalities and Quadratic story problems

    Question 1: A hospital dietitian wishes to prepare a corn-bean vegetable dish which will provide at least 40 grams of carbs, and cost no more than \$0.36 per serving. 28 grams of corn provide 8 grams of carbs and cost \$.04. 30 grams of beans provide 5 grams of carbs and cost \$.03. For taste...
  22. T

    Solving a system of Inequalities

    Hello, I'm having some trouble with a Queuing Networks question, not the networks but solving a system of inqualities based on the network. Homework Statement I have to find the value of α that gives maximum γ, and then use the value. The system is defined by 5\gamma< 1 20\gamma \alpha<1...
  23. S

    Exponential Inequality Challenge: Simplify and Solve for x

    Homework Statement (5 + √24)x + (5 - √24)x > 98 Homework Equations inequalities exponential The Attempt at a Solution I don't know how to start...trying to put log to both sides could not take me anywhere because the LHS can't be simplified...
  24. O

    Proof of \sqrt{ab}>\frac{2ab}{a+b} for Positive and Unequal Integers

    Can anyone help me confirm if I've solved this correctly? Many thanks. Homework Statement Prove that \sqrt{ab}>\frac{2ab}{a+b} if a & b are positive & unequal. Homework Equations The Attempt at a Solution if (\sqrt{ab})^2>(\frac{2ab}{a+b})^2 if ab>\frac{4a^2b^2}{(a+b)^2} if...
  25. S

    Inequalities find the set of values of x

    find the set of values of x for which 2x > \dfrac{3x + 1}{x+1} done this and got -1<x<-0.5, x > 1 b) find the set of inequalities where 2sint > \dfrac{3sint + 1}{sint + 1} where -\pi < t < \pi first I found the set values of t suitable in the range for -1,-0.5,1 which I got to be as...
  26. A

    Solving Hard Inequalities: 1/(x+4)>x-4 & 1/(x+7)>x-7

    I am looking at questions like 1/(x+4)>x-4 or 1/(x+7)>x-7 I have no idea how to solve them, I have simplified to (-x^2+50) /(7+x) however I don't think it is correct and I don't know what do do from there.
  27. O

    Solving Rational Inequalities: x < 2/(5x-1) | My Final Answer Matches Textbook!

    My final answer matches that of the textbook, but do I need to change the < to > at any point as I solve this? I ask because, if I assume x is 1 (until I solve for x), then the question statement and parts of the solution are made untrue. Homework Statement Solve the following for x...
  28. O

    Solving Abstract Inequalities: Proving (a+b)(a-b) = 0 for Positive a and b

    Homework Statement The final answer I have of (a+b)(a-b) does not appear to fit the textbook's required "results of inequalities which hold true for all real no.s", i.e. either: 1. (a)^2 or (a-b)^2 or 2. -(a+b)^2. Can anyone confirm if I have solved this correctly, in line with the conditions...
  29. D

    MHB Proving Schwarz's & Triangle Inequalities for Infinite Sequences

    I am not getting anywhere with this problem. Prove the Schwarz's and the triangle inequalities for infinite sequences: If $$ \sum_{n = -\infty}^{\infty}|a_n|^2 < \infty\quad\text{and}\quad \sum_{n = -\infty}^{\infty}|b_n|^2 < \infty $$ then $\displaystyle\left(\sum_{n = -\infty}^{\infty}|a_n +...
  30. D

    Efficient Methods for Solving Quadratic Inequalities

    Homework Statement Hi, there are several methods to solve an quadratic inequality. 1:by graph 2:if (x-a)(x-b) > 0,(x-a) > 0 and (x-b) > 0 or (x-a) < 0 and (x-b) < 0... 3.Using test value method i.e.Find a and b in the expanded form of (x-a)(x-b) a and b are the critical...
  31. D

    Can Complex Numbers Be Ordered to Form an Ordered Field?

    Hi, I am trying to solve x^2 - 10x + 26 < 0 Here are my steps: 1.Find the roots of x by using quadratic formula: x = [10 ± √(100-104)]/2 = 5±i 2.Rewrite x^2 - 10x + 26 into [x-(5+i)][x-(5-i)] 3.Now we have: [x-(5+i)][x-(5-i)]<0 x-(5+i) < 0 and x-(5-i) > 0 or x-(5+i) > 0...
  32. D

    Solving Absolute Value Inequalities: A Deeper Understanding

    I was hoping someone could give a little more insight, or perhaps enlighten me to a better way of approaching solving these seemingly simple Algebra 2 inequalities. I did some google searching but I was not able to find the answers I seek. The problem came up when a friend of mine had an...
  33. F

    What Are the Possible Values of the Larger Number in This Inequality Problem?

    Homework Statement The product of two numbers is less than 340. One of the numbers is 3 less than the other. What are the possible values of the larger number?Homework Equations The Attempt at a Solution Hope this is right... xy < 340 then, because y=x-3 x(x-3) < 340 x^2 -3x -340 < 0...
  34. V

    Equations describing a shaded region (inequalities)

    Homework Statement Question 42 in particular. Homework Equations No idea. The Attempt at a Solution The graph depicts an inequality of sorts, like y >= x and y >= -x as well as y <= x and y <= -x. Beyond these basic deductions (which are probably wrong also), I've not a scintilla of clue...
  35. T

    Algebra inequalities and exponents

    I have been stuck on two question for sometime, and would appreciate some guidance to where I am going wrong. Here are the two questions I seem to have trouble understanding. 1. 2x+5 < x-1/4 I have had numerous attempts at this equation and seem to get the answer wrong each time. The book...
  36. F

    EASY QUESTION solving system of linear inequalities

    Hello, I am stuck on something so simple. The problem is i have a great difficulty with the geometric interpretation of things.So if I have a system of linear equations in three unknowns, like for example this: -x - 2y + z = 0 x - 3y - 2z = 0this is just a simple system of homogeneous...
  37. D

    Mmmmmm Something very interesting I found about inequalities

    So I was brainstorming:bugeye: trying to find what I did wrong in this chemistry problem: https://www.physicsforums.com/showthread.php?t=627731 (simple algebra no chemistry knowledge required) And I noticed something peculiar about the process of solving inequalities, let me sum up in a phrase...
  38. azizlwl

    Maybe triangle inequalities theorem

    Homework Statement Prove: If a2+b2=1, and c2+d2=1, then ac+bd ≤1 Homework Equations Maybe triangle inequalities theorem. The Attempt at a Solution
  39. K

    Basics of Inequalities: Solving |x-1| - |x| + |2x+3| > 2x +4

    Can we explain the meaning of the modulus(absolute value) with these equations? |x| > a =>x > a or x < -a(if a \in R+ and x \in R if a \in R- |x|<a => -a < x < a if a \in R+ and no solution if a \in R-\cup{0} If yes, then examples please?(for instances in x and a) Blindly apply these...
  40. C

    Very Simple Inequalities Proof

    Homework Statement Prove the following inequalities for all numbers x, y. |x+y| ≥ |x|-|y| [Hint: Write , and apply , together with the fact that Homework Equations These were given as hints in my textbook: x=x+y-y |a+b| ≤ |a| + |b| |-y|=|y| The Attempt at a Solution...
  41. K

    Quadratic equations and inequalities

    Well suppose for an example of an inequality, |x-1|-|x|+|2x+3| > 2x+4 Well in one of its solutions we were told to apply the method of intervals, rather than taking say what; like 8 combination of signs. For everyone of its intervals(say -3/2 \leqx <0) we are said that 2x+3 \geq 0, x<0...
  42. K

    Square roots in quadratic trinomial inequalities

    How do we treat expressions under a sqaure root in inequalities ? Like for ex. x+4< Math.sqrt(-x^2-8x-12) (sorry, using m.physicsforums, so i don't know what to use for a root, so JAVA :p) I request the use of this very example.
  43. phosgene

    Sketching inequalities involving complex numbers

    Homework Statement Sketch all complex numbers z which satisfy the given condition: |z-i|\geq|z-1| Homework Equations z=a+bi |z|=\sqrt{a^{2}-b^{2}} The Attempt at a Solution First I find the boundary between the regions where the inequality holds and does not hold by...
  44. A

    Triangle Inequalities Relationship

    I know the following |x|-|y| \leq |x+y| \leq |x| + |y| where does |x-y| fit in the above equation?
  45. phosgene

    Inequalities between a real number and an imaginary number

    Homework Statement I'm just having a problem with a step that's part of a larger problem. Specifically, if I have: \sqrt{2}i\leq\sqrt{2} I'm not sure what this actually means. If I ignore the i, each side is the same distance from the origin if I imagine both points on a graph...
  46. R

    Why are we dividing by x in the solution for this limit problem?

    I am studying unit on limits and one of the example given to prove and established limit simply doesn't make sense. in the given solution of the example righhand side is simply not making sense to me - please see attached document and anyone can throw some light on this will be great so i can...
  47. B

    What does this example say about the applicability of Bell's inequalities?

    It is commonly believed that Bell's inequalities are a theoretical derivation of a condition that must be satisfied by locally causal theories. Therefore, it is often concluded that violation of these inequalities by experiments provides very strong evidence (if not conclusive proof, the only...
  48. N

    Solving absolute value inequalities

    Homework Statement [abs(x)]/[abs(x+2)]<2 Homework Equations The Attempt at a Solution case 1: [abs(x)]/[abs(x+2)]<2 case 2: [abs(x)]<2[abs(x+2)] is this right so far? if so, why is there two cases and what do i do next?
  49. N

    Solving inequalities (need some clarification)

    Homework Statement Solve x/(x-2) > 2 by first rewriting it in the form P(x)/Q(x)>0 Homework Equations The Attempt at a Solution well... i got up to x/(x - 2) > 2 x/(x - 2) - 2 > 0 x/(x - 2) - 2(x - 2)/(x - 2) > 0 x/(x - 2) - (2x - 4)/(x - 2) > 0 (x - 2x + 4)/(x - 2) > 0 (-x...
  50. L

    Critical point exponents inequalities - The Rushbrooke inequality

    The Rushbrooke inequality: H=0, T\rightarrow T_c^- C_H \geq \frac{T\{(\frac{\partial M}{\partial T})_H\}^2}{\chi_T} \epsilon=\frac{T-T_c}{T_c} C_H \sim (-\epsilon)^{-\alpha'} \chi_T \sim (-\epsilon)^{-\gamma'} M \sim (-\epsilon)^{\beta} (\frac{\partial M}{\partial T})_H \sim...
Back
Top