Inequality Definition and 1000 Threads

  1. A

    Stuck on Proof by induction of 2^n>n^3 for all n>=10

    Homework Statement Using the principle of mathematical induction, prove that for all n>=10, 2^n>n^3 Homework Equations 2^(n+1) = 2(2^n) (n+1)^3 = n^3 + 3n^2 + 3n +1 The Attempt at a Solution i) (Base case) Statement is true for n=10 ii)(inductive step) Suppose 2^n > n^3 for some integer >=...
  2. P

    When is the Cauchy-Schwartz inequality as large as possible?

    The Cauchy-Schwartz inequality (\sum_{i=1}^n x_i^2)(\sum_{i=1}^n y_i^2) - (\sum_{i=1}^n x_iy_i)^2 \geq 0 holds with equality (or is as "small" as possible) if there exists an a \gt 0 such that x_i=ay_i for all i=1,...,n . But when is the inequality as "large" as possible? That is, can we...
  3. C

    MHB Interval Notation of Inequality: -9<1/x<=1

    I need help determining the interval notation of the inequality below: -9<1/x<=1
  4. Steve Turchin

    Complex absolute value inequality

    Solve the following inequality. Represent your answer graphically: ## |z-1| + |z-5| < 4 ## Homework Equations ## z = a + bi \\ |x+y| \leq |x| + |y| ## Triangle inequality The Attempt at a Solution ## |z-1| + |z-5| < 4 \\ \\ x = z-1 \ \ , \ \ y = z-5 \\ \\ |z-1+z-5| \leq |z-1| + |z-5| \\...
  5. O

    MHB Triangle Inequality and Convergence of ${y}_{n}$

    Let ${y}_{n}$ be a arbitrary sequence in X metric space and ${y}_{m+1}$ convergent to ${x}^{*}$ in X...İn this case by using triangle inequality can we say that ${y}_{n}\to {x}^{*}$
  6. J

    Help in proving this inequality

    Can somebody help me please, I've tried solving this for hours but I still couldn't get it. Given that a, b, c, d are positive integers and a+b=c+d. Prove that if a∗b < c∗d, then a∗log(a)+b∗log(b) > c∗log(c)+d∗log(d) How do I do it?
  7. L

    Understanding Quadratic Inequality: Explained in Detail

    Can someone explain to be in detail what is quadratic inequality? It's rather confusing. Thank you
  8. anemone

    MHB Prove Inequality for $x,y,z$ Positive Real Numbers

    Given $x,\,y,\,z$ are positive real numbers. Prove that $\dfrac{xy}{x^2+xy+y^2}-\dfrac{1}{9}+\dfrac{yz}{y^2+yz+z^2}-\dfrac{1}{9}+\dfrac{zx}{z^2+zx+x^2}-\dfrac{1}{9}\le \dfrac{2\sqrt{xy+yz+zx}}{3\sqrt{x^2+y^2+z^2}}$
  9. anemone

    MHB Solving Inequality Problem: Proving Radical Expressions with Cube Roots

    Prove $\sqrt[3]{1−12\sqrt[3]{65^2} + 48\sqrt[3]{65}} -\sqrt[3]{63}\gt \sqrt[3]{1−48\sqrt[3]{63} + 36\sqrt[3]{147}} -4 $
  10. N

    Proving the Inequality: sin(x) < x for x > 0

    Hello all, I want to prove the following inequality. sin(x)<x for all x>0. Now I figured that I put a function f(x)=x-sin(x), and show that it is increasing for all x>0. But this alone doesn't prove it. I need to show we have inequality from the start. I can't show that lim f(x) as x->0 is...
  11. moondaaay

    Solve Quadratic Inequality: x²-4x+3≤(3x+5)(2x-3)

    Homework Statement How to solve this kind of inequality? x²-4x+3≤(3x+5)(2x-3)Homework EquationsThe Attempt at a Solution :[/B] I'm confused. Should I factor the left side or should I FOIL the right side then equate it to zero to find the critical numbers? Help pleaasee.
  12. RJLiberator

    Cauchy-Schwartz Inequality Proof

    Homework Statement Show that |<v|w>|^2 ≤ <v|v><w|w> for any |v>,|w> ∈ ℂ^2 Homework EquationsThe Attempt at a Solution The Cauchy-Schwartz inequality is extremely relevant for the math/physics that I am interested in. I feel like I have a very good proof here, but I am interested in a few...
  13. moondaaay

    How do I solve absolute value inequalities involving polynomials?

    1. Homework Equations Solving Polynomial Inequalities The Attempt at a Solution Then I used the property of absolute value inequality to get rid of it. But I really don't know if I'm doing the right step. Is this correct? So that I could separate them in two cases and find the...
  14. J

    B Absolute Value Inequalities: Solving for x

    Please help me. What is the next step to get rid of the absolute value? I tried using its property but I don't know if its correct.
  15. E

    Polynomial Inequality Homework: Solving without Technology | Remainder Theorem

    Homework Statement solve 3x4+2x2-4x+6≥6x4-5x3-9x+2 Do not use technology (i.e.-graphing calculators) Homework Equations Remainder Theorem The Attempt at a Solution I set the inequality equal to zero -3x4+5x3+3x2+5x+4≥0 Checking all the Possible rational roots for a possible factors... none...
  16. anemone

    MHB Prove Inequality For $x,y,z>0$ When $xyz=1$

    For $x,\,y,\,z>0$ and $xyz=1$, prove $\sqrt{x^2+1}+\sqrt{y^2+1}+\sqrt{z^2+1}\le\sqrt{2}(x+y+z)$.
  17. G

    Is There a Positive Scalar That Can Make One Function Greater Than Another?

    Homework Statement Let ##f,g## be two real valued functions, defined on the segment ##[a,b]## and continuous on ##[a,b]##, such that ## 0 < g < f ##. Show there exist ##\lambda > 0 ## such that ## (1+\lambda) g \le f ## Homework Equations The Attempt at a Solution Set ##h = f/g##. Since...
  18. B

    How to solve an inequality with a fraction and a negative number?

    How do you solve x for the below inequality? ##\frac{a}{x^2} < -b## My attempt is: ##\frac{a}{x^2} + b < 0## ##\frac{a + bx^2}{x^2} < 0##
  19. icystrike

    Quadratic Inequality: Solving for x | No Quotes

    Homework Statement [/B] As attached Homework EquationsThe Attempt at a Solution [/B] The answer is stated as option A. However, my solution is -6≤x≤3; I can seems to find an option that fits the solution.
  20. M

    MHB Solve the inequality and graph the solution a real number line

    5/(x-1) - (2x)/(x+1) - 1 < 0 How does one solve this inequality?
  21. M

    MHB Solve the inequality and graph the solution on a real number line

    (3x - 5)/(x - 5) > 4 How does one complete this problem?
  22. lucasLima

    Help proving triangle inequality for metric spaces

    So, i need to proof the triangle inequality ( d(x,y)<=d(x,z)+d(z,y) ) for the distance below But I'm stuck at In those fractions i need Xk-Zk and Zk-Yk in the denominators, not Xk-Yk and Xk-Yk. Thanks in advance
  23. anemone

    MHB Prove Inequality: IMO $\frac{1}{x^4}+\cdots \geq \frac{128}{3(x+y)^4}$

    Prove $\dfrac{1}{x^4}+\dfrac{1}{4x^3y} + \dfrac{1}{6x^2y^2}+ \dfrac{1}{4xy^3}+ \dfrac{1}{y^4} ≥ \dfrac{128}{3(x+y)^4}$, given $x,\,y$ are positive real numbers.
  24. Soumalya

    Development of Clausius Inequality

    I am facing some doubts trying to understand the illustration my textbook has adopted for the development of the Clausius inequality for thermodynamic cycles.I have attached an image of the content from my textbook. As one could see the author has assumed a closed system connected to a thermal...
  25. anemone

    MHB Prove: Inequality $9\gt \sqrt{a-1}+\sqrt{19-3a}+\sqrt{2a+9}$

    Prove that $9\gt \sqrt{a-1}+\sqrt{19-3a}+\sqrt{2a+9}$ for all real $a$.
  26. DrChinese

    A Experimental loophole-free violation of a Bell inequality

    A great new experiment is reported closing simultaneously the loopholes of detection (fair sampling assumption) and distance (locality assumption): Experimental loophole-free violation of a Bell inequality using entangled electron spins separated by 1.3 km B. Hensen, H. Bernien, A.E. Dréau, A...
  27. anemone

    MHB Show at least one of the inequality must be true

    Let $a_1,\,a_2,\,\cdots,\,a_{12}$ be positive numbers. Show that at least of the following must be true: $\dfrac{a_1}{a_2}+\dfrac{a_3}{a_4}+\dfrac{a_5}{a_6}+\dfrac{a_7}{a_8}+\dfrac{a_9}{a_{10}}\ge 5$, $\dfrac{a_{11}}{a_{12}}+\dfrac{a_2}{a_1}+\dfrac{a_4}{a_3}+\dfrac{a_6}{a_5}\ge 4$, or...
  28. Cosmophile

    Why Does \(\ln \frac{(x+1)}{(x-1)} \geq 0\) Imply \(x > 1\)?

    Homework Statement \ln \frac{(x+1)}{(x-1)} \geq 0 Homework Equations \ln \frac {a}{b} = \ln a - \ln b \ln \frac {(x+1)}{(x-1)} = \ln (x+1) - \ln (x-1) The Attempt at a Solution \ln (x+1) \geq \ln (x-1) e^{\ln (x+1)} \geq e^{\ln (x-1)} (x+1) \geq (x-1) According to Wolfram, the...
  29. E

    What is wrong with this inequality?

    Hello all, I have this formula ##\left[2\sqrt{Q\left(\sqrt{2\eta}\right)}\right]^N## where Q is the Q Gaussian function which can be upper bounded by the Chernoff bound ##Q\left(\sqrt{2\eta}\right)\leq exp\left(-\eta\right)##, and thus the original formula can be upper bounded as...
  30. D

    Bell inequality violated with classical light in experiment

    https://www.osapublishing.org/optica/fulltext.cfm?uri=optica-2-7-611&id=321243 "In our experimental test, we used light whose statistical behavior (field second-order statistics) is indistinguishable from classical, viz., the light from a broadband laser diode operating below threshold. Our...
  31. anemone

    MHB Prove Inequality: $(x+y)^2/2+ (x+y)/4 \ge x\sqrt{y}+y\sqrt{x}$

    Prove $\dfrac{(x+y)^2}{2}+\dfrac{x+y}{4}\ge x\sqrt{y}+y\sqrt{x}$.
  32. anemone

    MHB Solve Inequality Challenge: Prove $35\sqrt{55}+55\sqrt{77}+77\sqrt{35}\gt 2310$.

    Prove $35\sqrt{55}+55\sqrt{77}+77\sqrt{35}+35\sqrt{77}+55\sqrt{35}+77\sqrt{55}\gt 2310$.
  33. O

    MHB Generalized triangle inequality in b-metric spaces

    How is the generalized triangle inequality in b-metric spaces ? I find something...But I wonder your opinion...Thank you for your attention... Especially if you write for n,m>0 m>n $d({x}_{n},{x}_{m})$$\le$..... I will be happy...
  34. O

    MHB Triangle inequality in b-metric spaces

    Let $X$ be a non-empty set and let $s\ge1$ be a given real number. A function $d:$ X $\times$ X$\to$ ${R}^{+}$ , is called a b-metric provided that, for all x,y,z $\in$ X, 1) d(x,y)=0 iff x=y, 2)d(x,y)=d(y,x), 3)d(x,z)$\le$s[d(x,y)+d(y,z)]. A pair (X,d) is called b-metric space. İt is clear...
  35. Albert1

    MHB Inequality Challenge: Prove $\sum \frac{x^3}{x^2+xy+y^2}\geq\frac{a+b+c}{3}$

    $a,b,c \in N$,prove : $\dfrac{a^3}{a^2+ab+b^2}+\dfrac{b^3}{b^2+bc+c^2}+\dfrac{c^3}{c^2+ca+a^2}\geq\dfrac{a+b+c}{3}$
  36. Rectifier

    Can the minimum value of x + 1/x ever be less than 1 on x > 0?

    The problem I want to solve the following inequality: $$ x+\frac{1}{x}<1 $$ The attempt ## x+\frac{1}{x}<1 \\ x+\frac{1}{x}-1<0 \\ \frac{x^2}{x}+\frac{1}{x}-\frac{x}{x}<0 \\ \frac{x^2-x+1}{x}<0 ## ## x \neq 0 ## I tried to factor the numerator to examine the polynomial with a character table...
  37. anemone

    MHB Inequality Proof: $\dfrac{2015}{(k+1)(k+4030)}<\dfrac{1}{k+1}$

    Suppose $k>0$. Show that $\dfrac{2015}{(k+1)(k+4030)}<\dfrac{1}{k+1}-\dfrac{1}{k+2}+\dfrac{1}{k+3}-\dfrac{1}{k+4}+\cdots+\dfrac{1}{k+4029}-\dfrac{1}{k+4030}$.
  38. ognik

    MHB Reverse triangle inequality with a + sign

    Thought I knew this, but am confused by the following example: Show $ |z^3 - 5iz + 4| \ge 8 $ The example goes on: $ |z^3 - 5iz + 4| \ge ||z^3 - 5iz| - |4|| $, using the reverse triangle inequality It's probably right, but I don't get why the +4 can just be made into a -4 ?
  39. A

    Squaring both sides of equation and inequality?

    What is a square of a number? A^2=A*A. If A=B squaring both sides will give A^2=B^2. How I think about squaring is we multiply both sides of A=B by A(we could also do this for B) we get A*A=B*A but A=B so this will result in A*A=B*B. But if we do this for an inequality, A>B, multiplying both...
  40. toforfiltum

    Find inequality for coefficient of restituition

    Homework Statement A small smooth sphere of mass 3 kg moving on a smooth horizontal plane with speed 8 ms-1 collides directly with a sphere of mass 12 kg which is at rest. Given that the spheres move in opposite directions after the collision, obtain the inequality satisfied by e. Homework...
  41. A

    Understanding Schwarz Inequality and Its Role in Higher Dimensions

    Hello, I'm having a small problem with Schwarz inequality, |u⋅v|≤||u||||v|| the statement is true if and only if cosΘ≤1 !, I'm familiar with this result but how could it be more than 1? what is so special in higher dimensions that it gave the ability for cosine to be more than 1...
  42. Albert1

    MHB Proof of $a^{2a}\times b^{2b}\times c^{2c}>a^{b+c}\times b^{c+a}\times c^{a+b}$

    given : $a>b>c>0$ prove : $a^{2a}\times b^{2b}\times c^{2c}>a^{b+c}\times b^{c+a}\times c^{a+b}$
  43. A

    Adding increasing fractions without averaging numerators

    I'm interested in the following inequality (which may or may not be true) Theorem 1: ##( \sum_{i=1}^n \frac{a_i} {n}\ )( \sum_{i=1}^n \frac{1} {b_i}\ ) > \sum_{i=1}^n \frac{a_i} {b_i}\ ## Where ##n ≥ 2, a_1 < a_2 < ... < a_n## and ##b_1 < b_2 < ... < b_n##. My attempt at a proof: 1) When n =...
  44. evinda

    MHB Why Does the Minimum Value of u(x,y) Occur on the Boundary of the Unit Disk?

    Hello! (Wave) Let $u(x,y), x^2+y^2 \leq 1$, a solution of $$u_{xx}(x,y)+2u_{yy}(x,y)+e^{u(x,y)}=0, x^2+y^2\leq 1$$ Show that $\min_{x^2+y^2 \leq 1} u(x,y)= \min_{x^2+y^2=1} u(x,y) $. We suppose that $\min_{x^2+y^2 \leq 1} u(x,y) \neq \min_{x^2+y^2=1} u(x,y) $.At the solution it is said...
  45. P

    Bell's Inequality - A misintepretation of probability?

    I recently attended a presentation on the fundamentals of quantum mechanics which focused on the most recent experimental tests on Bells Inequality. As part of the introduction the speaker derived Bells Inequality. The speaker made it sound very straightforward and it was, the proof was a piece...
  46. Rectifier

    Is x=0 a solution to the inequality above?

    Homework Statement $$x+\frac{16}{\sqrt{x}} \geq 12$$ How do I show that only x>0 satisfies the inequality above. Homework EquationsThe Attempt at a Solution I have not made a lot of progress here. I tried the following: $$x+\frac{16}{\sqrt{x}} - 12 \geq 0$$ I tried to multiply with $$...
  47. anemone

    MHB Inequality Challenge: Prove $1/(u-1)+1/(v-1)+1/(x-1)+1/(y-1)>0$

    Real numbers $u,\,v,\,x,\,y$ satisfy the following conditions: $|u|>1$, $|v|>1$, $|x|>1$, $|y|>1$, and $u+v+x+y+uv(x+y)+xy(u+v)=0$ Prove that $\dfrac{1}{u-1}+\dfrac{1}{v-1}+\dfrac{1}{x-1}+\dfrac{1}{y-1}>0$.
  48. T

    What Values of \( p \) Ensure \( p(x^2+2) < 2x^2+6x+1 \) for All \( x \)?

    Homework Statement What is the set of values of p for which p(x^2+2) < 2x^2+6x+1 for all real values of x? Homework Equations p(x^2+2) < 2x^2+6x+1 3. The Attempt at a Solution I know I need to use my knowledge of the discriminant here, but the fact that its an inequality is confusing me...
  49. M

    Solving Inequalities: How Do I Determine the Correct Answer?

    How would I solve the inequality (X-4)/X>0. I thought that inequalities were solved in the same way equations were, but when I solve that way I get X>4 which isn't the entire answer.
  50. P

    Proof of Cauchy-Schwarty Inequality

    Proof of Cauchy-Schwarty Inequality from the Book "Quantum Mechanics Demystified" Page 133. I do not understand one key step! Most appreciated someone could help. Please see attached file.
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