Induction Definition and 999 Threads

  1. I

    Abstract Algebra Proof by induction problem

    Homework Statement Show via induction that the nth root of (a1 * a2 * a3 * ... an) ≤ 1/ (n) * ∑ ai, where i ranges from 1 to n. Homework Equations Induction The Attempt at a Solution Let Pn be the statement above. It is clear that P1 holds since a1 ≤ a1. Now let us assume that Pn...
  2. O

    Calculating Frequency for Induction Motors with Given Horsepower and Pole Count

    Hello I'm doing a question in induction motor now. formula for Induced torque is Pgap / Ws. i have found the Pgap, but in order to find Ws, i need frequency to find ns.. so my question is, how to find frequency with only given 10hp and four pole
  3. K

    MHB Proving the Recursion Formula for $(x_n)$ Using Strong Induction

    Let $(x_n)$ be a sequence given by the following recursion formula: $$x_1 = 3, x_2 = 7,\text{ and }x_{n+1} = 5x_n - 6x_{n-1}$$ Prove that for all $n\in\Bbb N$, $x_n = 2^n + 3^{n-1}$. Attempt: For $n = 1$, we have $2^1 + 3^0 = 3 = x_1$ TRUE For $n = 2$, we have $2^2 + 3^1 = 7 = x_2$ TRUE...
  4. F

    Understanding Faraday's Law: The Role of Magnetic Flux and Imaginary Surfaces

    Hi, please could someone help explain how magnetic flux works in Faraday's law as I struggle with electromagnetism. From what I understand, if you have a loop of wire in a magnetic field then you get an induced current if the flux is both changing and perpendicular to the plane of the loop...
  5. N

    MHB Solve Induction Problem: cn <= n log2n

    Hey I've been given an equality to solve as a bonus question with a strong hint that a like one would appear on my midterm. However, I am stumped by it, it appears quite complex to me. Any insight into how to solve this would be greatly appreciated! I'll try to type it as best I can: A student...
  6. S

    How Do I Safely Power My Induction Motor for a Class Project?

    I'm planning on building a simple induction motor for my class project and am hoping someone might have some advice about powering the motor. I feel a little ridiculous asking but I had almost no understanding of electricity prior to the beginning of my Physics 212 class and the textbook doesn't...
  7. R

    What is the inductive step for proving mathematical induction?

    Hey! I've just started to learn some mathematical induction and it's proving quite tricky. Hopefully someone could help me out a little with my questions! I don't know how to format question on this forum but I'll try my best to accurately represent it: n $$sigma$$ i * 2^i = (n-1) * (2^n+1) +...
  8. MarkFL

    Jay's question at Yahoo Answers regarding a proof by mathematical induction

    Here is the question: I have posted a link there to this thread so the OP can see my work.
  9. Omega0

    What is the role of free electrons in electric induction?

    Hi, I have been told that you take say a metal board and another board (both endless and paralell) leads to the following effect: The electrons are more or less freel in motion, they move to the surface until we reach an equilibrium. The electrons are assembled at the surface. Nice...
  10. S

    Explaining the Inconsistency and Solution in Faraday's Law of Induction

    Homework Statement Why does the Faraday Law of Induction not suffer from the inconsistency encountered with the Ampere Law? Homework Equations \oint E * dl = - (N) d/dt \intB * dA The Attempt at a Solution The Ampere Law is inconsistent with the time varying equation of...
  11. W

    Sound Wave, Microphone and Electromagnetic Induction

    Dear all, I have encountered an issue in understanding how microphone works and I hope you guys can assist. There are two scenarios involved. In the first scenario, there is tuning fork and a microphone. The microphone contains a small disc attached to a magnet and a fixed coil. (Please...
  12. L

    Prove by Induction: Un = 1/2(1 - 1/22^n)

    Homework Statement The sequence {Un} is defined by the recurrence relation Un+1 = 2Un(1-Un), n≥0, U0 = 1/4 Prove by Induction that Un = 1/2( 1 - 1/22^n )I'm sorry I didn't know how to type this any better the 2 is raised to the power of 2 and that 2 is raised to the power of n The Attempt...
  13. M

    Why is Axiom of Induction Needed as an Axiom? (Peano's Axioms)

    I've already asked somebody through email this question, so I'll copy and paste part of my email: Basically, I'm wondering why doesn't it fall from the other axioms, and if it does in fact not fall from the other axioms (which it apparently doesn't), why the axioms can't be slightly modified...
  14. S

    Proving an Inequality by Induction

    Homework Statement Question: Use induction to prove that 3^n > n x 2^n for every natural number n ≥ 3 Homework Equations N/A The Attempt at a Solution Answer: Step 1: 3^3 > 3 x 2^3 ⇒ 27 > 24 Step 2: Assume 3^k > k x 2^k Step 3: 3^(k+1) > (k+1) x 2^(k+1) ⇒ 3 x 3^k > k x 2^(k+1) +...
  15. srfriggen

    Induction Proof with combination

    Homework Statement Prove: \sum^{n}_{r=0}2r(^{n}_{r}) = 3n Homework Equations The Attempt at a Solution I proceeded by induction: Testing the base case for n=0 is correct. Moving right along to try to show: \sum^{n+1}_{r=0}2r(^{n}_{r}) = 3n+1 This is where...
  16. M

    Engineering V / F constant control of induction motor with inverter

    Hello. I have to do an experiment on this topic, but there are many things I don't know. First of all, can you tell me what do the symbols V~ and A~ mean?
  17. S

    Polarization of Electromagnetic Wave and Faraday's Law of Induction

    Homework Statement Hey guys. I have an electromagnetic wave traveling in the z direction and polarized in the x direction. The frequency is 1 MHz and average power density is 1 W/m^2. An antenna in the shape of a circular wire is in the xy-plane centred at the origin. I would like to use...
  18. K

    MHB Can Every Integer Be Decomposed into an Odd Integer and a Power of 2?

    Prove that every n E N can be written as a product of odd integer and a non-negative integer power of 2. For instance: 36 = 22 * 9
  19. K

    MHB Induction for divisibility by 10

    Show that for every n∈N, 34n+2 +1 is divisible by 10 Prove by Induction. Attempt) Base Case: n = 1, 3(4(1)+2) + 1 = 730 So the base case holds true. Assume that the inequality holds for n = k 34k+2 +1 is divisible by 10 Show true for n = k+1 34(k+1)+2 + 1 34k+4+2 + 1 34 * 34k+2 + 1 81 *...
  20. K

    MHB Induction for series of squares

    Prove that for all nEN 1^2 + 3^2 + 5^2 + ... + (2n-1)^2 = (4n^3 - n) / 3My Solution) If n = 1, 4(1)^3 - 1 / 3 = 1 so base case holds. Assume 1^2 + 3^2 + ... + (2k-1)^2 = (4k^3 - k) / 3 What next?
  21. R

    Some Qustions of Electrostatic Induction

    Hi Q 1 An electrified rod attracts pieces of paper. After a while these papers fly away. Why? My Answer: Due to the phenomenon of electrostatic induction, the paper becomes charged and will be attracted towards the rod. After some time, the charge becomes neutral and paper flies. Q...
  22. K

    MHB Prove 1/√n Inequality by Induction

    Prove this inequality by induction for all nEN: 1/√1 + 1/√2 + 1/√3 + ... + 1/√n >= √n
  23. P

    Binomial theorem proof by induction

    On my problem sheet I got asked to prove: ## (1+x)^n = \displaystyle\sum _{k=0} ^n \binom{n}{k} x^k ## here is my attempt by induction... n = 0 LHS## (1+x)^0 = 1 ## RHS:## \displaystyle \sum_{k=0} ^0 \binom{0}{k} x^k = \binom{0}{0}x^0 = 1\times 1 = 1 ## LHS = RHS hence true for...
  24. T

    Prove with mathematical induction

    With mathematical induction i should prove that is true for all natural numbers:http://img.tapatalk.com/d/13/10/18/u6epesu5.jpg Im sorry beacuse i have inserted an image,but I am still not used to write it in $$ here...
  25. Q

    How Does EMF Induce in a Solenoid Despite Minimal Flux Cutting?

    1. Assuming that both the windings of a transformer is wrapped around an iron core, how is an EMF induced in the secondary winding - isn't it necessary for flux to cut through the winding in order to induce an EMF? The flux cutting through the winding would apparently be very low..as most of it...
  26. H

    Induction coils and contact materials

    Hi, I'm using an induction coil to heat up an electrically conductive material within the coil. However, I'm worried that adjacent electrically conductive materials, which are not within the coil will also have see a heating effect, due to induction not thermal transfer. I want to avoid this as...
  27. S

    Induction to prove then number of subsets with elements of 3

    Homework Statement Prove that a set with n elements has \frac{n(n-1)(n-2)}{6} subsets containing exactly three elements whenever n is an integer greater than or equal to 3. Our professor wants us to use Induction. Homework Equations P(n) = \frac{n(n-1)(n-2)}{6} n \geq 3 The...
  28. M

    Solving Homework Problems with Induction: Step-by-Step Guide

    I am having issues with my homework questions, I can get them all the way to the very alst step but i seem to consistently get stuck trying to connect them to the answer at the end. (this will make more sense when you see the problem) I'm going to post both proofs I've worked on so far one after...
  29. skate_nerd

    MHB Inequality proof w/ induction, 2 unknowns

    I am given a statement to prove: Show (without using the Binomial Theorem) that \((1+x)^n\geq{1+nx}\) for every real number \(x>-1\) and natural numbers \(n\geq{2}\). I am given a hint to fix \(x\) and apply induction on \(n\). I started by supposing \(x\) is a fixed, real number larger than -1...
  30. N

    Induction Problem Related to Cars

    Induction Problem Related to Cars... Homework Statement A small electric car overcomes a 260N friction force when traveling 23km/h . The electric motor is powered by ten 12-V batteries connected in series and is coupled directly to the wheels whose diameters are 57cm . The 240 armature...
  31. srfriggen

    Proving Ʃ 1/√k ≥ 1/√n with Induction

    Homework Statement Ʃ 1/√k ≥ 1/√n (under sigma should be "k=1" and above should be "n", and n is a positive integer) Homework Equations The Attempt at a Solution I. Base case when n=1 is correct. II. Inductive Hypothesis: Assume true for k=m, where k<m<n, m is a positive...
  32. P

    Show by induction that (2n-1) /(2n) <= 1/(3n+1) for all n

    Show by induction that (2n-1)!/(2n)! <= 1/(3n+1) for all n Homework Statement Show by induction that (\frac{1\cdot3\cdot5\cdot\cdot\cdot(2n-1)}{2\cdot4\cdot6\cdot\cdot\cdot2n})^2 \leq\frac{1}{3n+1} for n=1,2,3, ... The Attempt at a Solution It might not really be relevant, but I've...
  33. K

    Prove by Induction that n ≥ 2^(n-1) n ≥ 1

    prove by Induction that n! ≥ 2^(n-1) n ≥ 1
  34. C

    Discrete math sequence and inequality induction proof help

    Hello. I am reading an introduction to induction example, and I am having the hardest time trying to determine what exactly happened in the proof. Can somebody please help? How can ##3^{k-1}## + ##3^{k-2}## + ##3^{k-3}## all of a sudden become ##3^{k-1}##+##3^{k-1}##+##3^{k-1}## and how can be...
  35. S

    MHB Proof By Induction: Proving Divisibility of 3^2n-1 by 8

    Hello Guys can you tell me how do i go about this question: Question Prove by Induction that for every positive integer n. $$3^{2n} -1$$ is divisible by 8
  36. C

    Induction, magnetism (flux), and current

    Hi, inductance is the property of a conductor by which a change in current in the conductor "induces" (creates) a voltage (electromotive force) in both the conductor itself (self-inductance). --wikipedia From what I understand, the inducing happens due to the resulting change in magnetic field...
  37. F

    MHB Strong induction hypothesis for statement about connected graphs

    Use strong induction to prove that if G is connected and every vertex has even degree that G has a Eulerian Circuit. a)verify the base case where G has no edges - done b)Write down the strong induction hypothesis that asserts the statement is true for all graphs that meet the hypotheses and...
  38. B

    Discrete math : Induction proof

    Stuck on the induction step,please help
  39. J

    Mathematical induction inequality

    Homework Statement Prove; n^2 > n+1 for n = 2,3,4 by Induction Homework Equations The Attempt at a Solution p(n)= P(2) 2^2> 2+1 --> 4>3 Induction step: P(n+1): (n+1)^2 > (n+1) +1 (n+1)^2> n+2 n^2 + 2n + 1 > n+2 | -n n^2 +n + 1> 2 | -1 n^2 +n > 1 Is this correct, and how...
  40. V

    Electromagnetic induction and conductor

    Hello everyone, One very basic thing about this phenomenon is not very clear to me. If a conductor moves in a region of uniform magnetic field, would it have an EMF induced across it? I'm confused because as per Faraday's law, a change in flux through the conductor is necessary for EMF to be...
  41. L

    Can we prove every number is even or odd without induction?

    It is a simple exercise to prove using mathematical induction that if a natural number n > 1 is not divisible by 2, then n can be written as m + m + 1 for some natural number m. (Depending on your definition of odd number, this can either be stated as "every number is even or odd", or as "every...
  42. A

    Does Inductive Reasoning Prove f(x) Equals x Squared for All Natural Numbers?

    This is from a functional equation , i think there is no points in posting it here this is what i ant to prove the functions is from N to N . let x be a natural number i want to prove that f(x)=x^2 By induction suppose that f(x)=x^2 f(0)=0 holds (from the functional equation) i want...
  43. J

    Power required from forced induction?

    I'm trying to calculate the power required from forced induction with this equation; W˙=m˙CpT1ηc⎡⎣(P2P1)(γ−1γ)−1⎤⎦ However I seem to be getting rather low results for work ~0.8W I have done my calculations in this spreadsheet. Any ideas where I've went wrong? thanks [SIZE="6"] Note...
  44. G

    MHB Complex Conjugates/Proof by Induction

    So I am having a bit of trouble with a proof by induction that I need to write. The problem is to prove that the conjugate of the product g1 * ... * gm equals the product of the conjugates of g1 ... gm. This is for g1 ... gm complex numbers. I have proven this for m = 2, by simple calculation...
  45. S

    MHB Can we prove $3^n > n^3$ for all $n \geqslant 4$ using induction?

    We wish to show that $3^n > n^3 \, , \ \forall n \geqslant 4 $. Base case $n = 4$ yields $3^4 = 81 > 4^3 = 64 $ Assume the inequality holds for $n = p $ i.e. $3^p > p^3$ for $p \geqslant 4$. Then $3^{p+1} > 3p^3$ $p \geqslant 4$ implies $3p^3 \geq 192$, as well as $(p+1)^3 \geqslant 125$...
  46. P

    Need help in finding some old papers on Induction effect

    Where and how can I find these two papers ? P. Debye, Physik. Z., 1920, 21, 178 H. Falckenhagen, Physik. Z., 1922, 23, 87 Thank you. Regards
  47. C

    Simple Proof by Induction Problem

    Hi, I devised this problem for myself as part of a bigger question that I'm working on, and am having trouble solving it. I think it involves a nested induction proof but I am not sure how to start. A tip on how to begin would be much appreciated. Thanks -Patrick Homework Statement S_0 =...
  48. R

    Magnetic Induction (Non-uniform Current)

    Homework Statement long wire of radius R0 carries a current density j given by Find the magnetic induction B inside and outside the wire. Homework Equations Current density: ##J=\frac{I}{A}## Ampere's law: ##\oint B.dl = \mu_0 I_{enc}## The Attempt at a Solution For the magnetic field...
  49. G

    Mathematical Induction where the base case starts above 1

    Homework Statement Find all natural numbers such that 2n ≥ (1+n)2, and prove your answer. 2. The attempt at a solution I can see this is true for n=0 and n>5. I try to prove this using induction as follows 20 =1≥ 1=(1+0)2 base case: 26 =64≥ 49=(1+6)2 so it is true for n=6 and suppose 2n...
  50. U

    Which case generates emf by electromagnetic induction

    1. a. coil is moved up and down in the same direction of flux. b. coil is rotated around an axis that is parallel to the flux. c. coil is rotated to the direction of the flux like a dynamo. 2. Electromagnetic inductions laws. 3. I'm really having a hard time...
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