What is Maximum: Definition and 1000 Discussions

In mathematical analysis, the maxima and minima (the respective plurals of maximum and minimum) of a function, known collectively as extrema (the plural of extremum), are the largest and smallest value of the function, either within a given range (the local or relative extrema), or on the entire domain (the global or absolute extrema). Pierre de Fermat was one of the first mathematicians to propose a general technique, adequality, for finding the maxima and minima of functions.
As defined in set theory, the maximum and minimum of a set are the greatest and least elements in the set, respectively. Unbounded infinite sets, such as the set of real numbers, have no minimum or maximum.

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  1. R

    Determine maximum weight and angle for equilibrium

    Homework Statement The cords ABC and BD can each support a maximum load of 100 lb. Determine the weight of the crate, and the angle θ for equilibrium. Homework Equations ∑F= 0 ∑Fx=0 ΣFy=0 Setting derivative of an expression to zero To find critical point Second derivative test for determining...
  2. R

    Heat Transfer maximum current a wire can carry

    Homework Statement A copper wire has a diameter of 204.3 mil (1 mil = 0.001 in) and a resistance per unit length of 8.31x10^-4 ohm/m. The wire is coated with plastic insulation with thermal conductivity k = 0.20 W/(m K). The upper temperature limit of the plastic is 400 K. The air surrounding...
  3. D

    Maximum voltage and current values for building a DC motor

    Hello, I am building a large DC motor for a Go-kart. I have a question: How would I know how much voltage and current (the maximum values I can use) I need to make the DC motor work and spin? I'm guessing the armature size and the winded wire's length depends on how much voltage and current...
  4. Nader AbdlGhani

    Optimizing Current Intensity: Connecting Cells in Series and Parallel

    Homework Statement How can I get the maximum Current Intensity by connecting 72 cells to a 3 Ohm resistor each cell has a potential difference of 1.5 Volt and internal resistance of 1 Ohm Please don't tell me to connect them all in parallel or all in series as in parallel the potential...
  5. C

    Where is the Local Maximum for y = (8/5)sin(t) + (4/5)cos(t) - (9/5)e^(-t/2)?

    Homework Statement y=(8/5)sint + (4/5) cost - (9/5)e^(-t/2) find its local max Homework EquationsThe Attempt at a Solution i have differentiated it and found out dy/dx, in order to find the local max, i have to find out the value t when dy/dx=0 but i can't solve this equation
  6. Dare Diamond

    Maximum Voltage To Apply To An Air core Electromagnet

    Hello everyone. I am glad I came across this science oriented Forum site. I actually get there from Google and what I am deeply curious to know about is the amount of Maximum Voltage my 3.5kg Air Core Electromagnet can bear. The Core of the Solenoid is 120mm in height and 13inches in...
  7. P

    Maximum Angular Velocity of an Electric Motor

    Hello! I was looking to find out about an equation that would tell you the maximum angular velocity an electric motor can put out in terms of the geometry of the motor (area of the rotating coil, number of turns, etc), the EMF applied to the coil, magnetic field surrounding the coil, and so on...
  8. Keith

    Is There a Limit to the Size of a Black Hole?

    I'm just curious, do black holes have a maximum size? In other words, if it theoretically had an infinite supply of matter to "feed" off of, would the black hole just get more and more massive or is there a point where it can no longer fit anymore matter? Will it just spit out hawking radiation?
  9. T

    Does a pump have a maximum flow rate for a given system?

    Hi everyone, I am an electrical engineering student and in my free time, I make educational youtube videos about electronics. (youtube.com/SolidStateWorkshop). I'm working on a video right now about transistors. To help explain their operation, I am attempting to use a hydraulic circuit...
  10. V

    Maximum mechanical energy in the spring-block system

    Homework Statement Homework EquationsThe Attempt at a Solution Suppose the free end of hte spring moves towards right .Consider a reference frame moving with speed 'v' along with the free end of the spring . From this frame ,the block has an initial speed 'v' towards left . At maximum...
  11. anemone

    MHB Find maximum and minimum of P

    Find the minimum and maximum of $P=\dfrac{y−x}{x+8y}$ for all real $x$ and $y$ that satisfy the equation $y^2(6-x^2)-xy-1=0$.
  12. L

    Maximum angle for 2D collision

    Homework Statement A mass m1, with initial velocity u, collides elastically with mass m2, which is initially at rest. After collision, m1 deflects by angle θ. Find the maximum value of θ. The answer given is θmax=acos(sqrt(1-(m1/m2)^2)). Does this mean that the maximum angle cannot exist if...
  13. ali nemati

    Maximum Thrust force in submarine

    I am designing a submarine in low scale that the max propeller OD is 10 cm, means from center of shaft to propeller edge I have around 5 cm distance. I am trying to find the maximum thrust as this submarine suppose to pull an object inside water pipe. I need to find optimum rpm ,blade number...
  14. O

    MHB Max A $\le$ Sup B: Is it True?

    for A$\subset$ B max A $\le$ sup B ? is it true ?
  15. Luke Cohen

    Maximum energy stored in a capacitor? RLC circuit

    Homework Statement The current in a series RLC circuit leads the generator voltage by φ = 30°. The circuit, containing an inductor L = 400 mH and a resistor R = 50 Ω, is driven by a generator operating at ω = 100 rad/s with a maximum emf of 10 V. The capacitance is unknown. The first question...
  16. praveena

    Which is the maximum speed that our human body can bear?

    The astronauts who were traveling to the space. in what way their health were affected? During the rocket launch the spacecraft should travel greater than the Earth's escape speed. Is this speed affect the astronaut? And tell me which is the maximum speed that our human body can bear?
  17. T

    Calculate maximum weight box can hold

    hi, This is probably very simple issue, but i am not an engineer nor have an understanding of basic physic... I need to calculate if the tape used to connect (sealed) to ends of the cardboard box will withstand the weight of the product i put inside it. I have a tape properties (tensile strength...
  18. K

    Maximum mass of a metal you can melt; Heat of Transformation

    Homework Statement What is the maximum mass of lead you could melt with 2000 J of heat, starting from 25 ∘C ? Lead melts at 328∘C , its specific heat is 128 J/(kg⋅K) , and its heat of fusion is 2.5×10^4 J/kg . Homework Equations Need to find both the mass in the heat of transformation (Q =...
  19. Julio1

    MHB Maximum Likelihood Estimators for Uniform Distribution

    Find maximum likelihood estimators of an sample of size $n$ if $X\sim U(0,\theta].$ Hello MHB :)! Can any user help me please :)! I don't how follow...
  20. E

    Communicating vases, maximum height before rest (water in pipes)

    I do not know much about computers too (not really true but I am not really up to date), I do not know if I am doing what I am supposed to, here is my first simple question: Two connected pipes, equal diameter (internal) 100 mm, same height (2200 mm), I have water in one pipe at 2000 mm, in the...
  21. Ketan Vadher

    How to calculate the max acceleration

    I have an engine with the following specifications: 305 cc, 4-stroke single-cylinder. Torque : 18.53 N m @ 2800 rpm. Weight of the car 275kg Coefficient of drag:1.15 Frontal area: 0.9177m^2 Rolling resistance:0.04482 Engine wheel efficiency: 78% How can i calculate the Max. acceleration and...
  22. Tonia

    How far does it take for an object to reach maximum velocity

    Homework Statement At what distance (OR at what time) does it take for an object falling at 32 ft per sec per sec. to reach terminal velocity in its descent?? Homework Equations The only equation I can think of to use here would be distance = (rate of descent) times time. The Attempt at a...
  23. S

    Maximum stress as percentage of Yield Strength

    Homework Statement Hi guys, I have a question here, which asks me to express the maximum stress from my simply supported beam, which I worked out to be 1.165MPa, to be expressed as a percentage of the Yield strength 95MN/m^2. I also have a follow on from that which asked me how much the...
  24. AwesomeTrains

    Maximum position expectation value for 1D harmonic oscillator

    Hey, I'm stuck halfway through the solution it seems. I could use some tips on how to continue. 1. Homework Statement I have to determine a linear combination of the states |0\rangle, |1\rangle, of a one dimensional harmonic oscillator, so that the expectation value \langle x \rangle is a...
  25. MidgetDwarf

    Can relative maximum and minimum exist when the derivative....

    Can relative maximum and minimum points exist when a function is defined at say x=c, however the derivative does not exist or tends to infinity? Ie the graph of. F (x)= |x|, for x=c=o. If I am correct the relative minimum is at o, can it also be the abs minimum? I recalled the theorem by...
  26. C

    Maximum voltage on coaxial cable?

    Homework Statement How to determine maximum voltage that coaxial cable, whose height is L and is filled with dielectric in such way that E is the same in the dielectric and in the part of the cable that isn't filled with dielectric (only vacuum),can handle if i have maximum electric field that...
  27. Mayzu

    Maximum extension of a bungee cord

    Homework Statement (a) An 81 kg student is launched from a bridge by his best friends, some 50 metres above the river surface. Fortunately, he is attached to a 30 m bungee cord with a spring constant of 270 N/m. i) What is the equilibrium length of the bungee cord, including the force of...
  28. freutel

    What is the speed when a disk has reached maximum extension?

    Homework Statement Two identical disks with mass m and radius r are connected via a massless wire of length L which is winded up around both disks. Disk B is connected to the ceiling and is free to rotate around its axis. Disk A is besides disk B and will fall due to the gravitational force...
  29. P

    Which Color Provides the Best Green House Effect for Pool Solar Covers?

    Hi, I have some thoughts about making a much better pool solar cover. My thoughts are to maximize the temperature increase. I plan to suspend a plastic film 6 inches above the surface of the pool water creating a green house effect. Normally, very small plastic are pockets are embedded in the...
  30. C

    Trying to Find Coords of a Local Maximum and Minimum

    Homework Statement (c) Show that ##tan(x) + cot(x) \equiv 2csc(2x)## (d) Hence or otherwise, find the coordinates of the local maximum and local minimum points of the graph of ##y = tan(2x) + cot(2x), 0≤x≤\frac{π}{2}## Homework Equations Most likely a lot of different trigonometric formulas to...
  31. T

    Ball with maximum velocity on reaching the ground.

    Homework Statement A ball A is thrown upward to a height H with a velocity of 20m/s, another ball B is thrown down from H with a velocity of 20m/s and a third ball C is just dropped from the same height. Find which ball has the maximum velocity when it hits the ground.Homework Equations...
  32. Rafael de Gomes

    Maple - Finding maximum of maximums in different functions

    Hello, I've been trying to come up with a short way of writing the code. What I'm trying to do is: I have 11 equations, each of which have a defined minimum and maximum. I'm trying to find the highest maximum out of all of them and I need to know which one it is. The highest as in farthest...
  33. M

    MHB Can the Maximum Principle be Used to Estimate Solutions of Elliptic Equations?

    Hey! :o Let $S=\{x \in \mathbb{R}^2 \mid |x| <1\}$. Using the maximum principle I have to show that the solution of the problem $$-\Delta u(x)=f(x), x \in S \\ u(x)=0, x \in \partial{S}$$ satisfies the estimation $$|u(x)| \leq \frac{1}{4}\max_{x \in \overline{S}} |f(x)|, x \in S$$ To use the...
  34. M

    MHB Maximum principle-Uniqueness of solution

    Hey! :o Let $\Omega$ a bounded space. Using the maximum principle I have to show that the following problem has an unique solution. $$u_t(x, t)-\Delta u(x, t)=f(x, t), x \in \Omega,t>0\\ u(x, t)=h(x, t), x\in \partial{\Omega}, t>0 \\ u(x, 0)=g(x), x \in \Omega$$ I have done the following...
  35. M

    MHB Max Principle: Showing $|u_1-u_2|\leq \max_{\partial{\Omega}}|g_1-g_2|$

    Hey! :o Let $\Omega$ a bounded space. Let $u_1$ the solution of the problem $$-\Delta u_1(x)=f(x), x \in \Omega \\ u_1(x)=g_1(x), x \in \partial{\Omega}$$ and $u_2$ is the solution of the problem $$-\Delta u_2(x)=f(x), x \in \Omega \\ u_2(x)=g_2(x), x \in \partial{\Omega}$$ Using the maximum...
  36. S

    Position and magnitude of the maximum bending moment

    Homework Statement I need to calculate the position and magnitude of the maximum bending moment. Knows are: E=210GPa Homework EquationsThe Attempt at a Solution I've calculated the following: R1=33kN R2=32kN From the shear force diagram I know that at 2m from R1 at the concentrated load of...
  37. L

    MHB Very dificult: The minimum perimeter and maximum height of a triangle under constraints

    Obtain -The maximum height corresponding to the side b of any triangle (abc) once known the value of its perimeter and height corresponding to the a side a. -The minimum perimeter of any triangle (abc) once known the heights corresponding to the a and b sides. Aux: Geogebra construction...
  38. S

    Equations for average and maximum velocity

    Homework Statement Given height dropped and gravity constant, what is the maximum and average velocity of an object dropped from a building. Gravity- 9.81 (Delta)y- 45 m. Height from which object is dropped T- 3.1 seconds Homework Equations V= v(final)-v(initial)= a x (delta)t V(avg)= (sqrt...
  39. S

    What does the maximum work of a reversible expansion mean?

    What does it mean by maximum work of an isothermal, reversible expansion of a perfect gas from initial volume Vi to final volume Vf at temperature T? I understand that heat enters the system during this expansion to ensure that no internal energy is lost but it doesn't really help in anyway...
  40. Q

    Max Power Transfer: Optimal Load for Piezo & EM Gen

    Hello everyone, I have two generators, piezoelectric and electromagnetic generator. Piezoelectrics are producing maximum voltage across 3 Mohm resistor where as EM generator is producing maximum voltage at 68 ohm. What would be the ideal load for to get the maximum output from both when...
  41. M

    MHB How Can Terrific Wears Inc. Maximize Revenue and Profit from Suit Sales?

    Terri c Wears Inc., a clothing rm determines that the demand for their suits is given by d = 2(175􀀀p), where d represents the demand and p represents the price of a suit. (Recall that Revenue=PriceDemand, Profi t=Revenue-Cost.) (1) Find the selling price for a suit that will generate maximum...
  42. J

    Maximum Entropy Information System

    Imagine a maximum entropy information system: This system would hold meaningful information, not just random noise, but still be of maximum possible entropy in the sense that you could randomly change the order of the smallest bits of information in it without actually changing the overall...
  43. S

    Maximum (cutoff) freq for a photoresistor

    Hi, I am working on a project where I want to use a photoresistor to measure displacement, by reflecting light off of a small component and measuring the light that is reflected. the goal is to measure vibration. I am having a hard time finding information on the cutoff frequencies of...
  44. S

    Finding maximum of a wavefunction?

    Homework Statement [PLAIN]http:// Question D. Homework Equations The Attempt at a Solution The wavefunction is all real. So I can simply sqaure it... However when I do this and differentiate it using the product rule, I'm getting r = 2a(naught) as the maximum and not 4a(naught)... Any...
  45. M

    MHB Maximum Value of k in $(1+\frac{1}{a})(1+\frac{1}{b}) \ge k$ is 9

    For any positive real numbers a, b such that $a+b=1$, the inequality $(1+\frac{1}{a})(1+\frac{1}{b})\ge k$. Find the maximum value of $k \in \Bbb{R}$. I did: $(1+\frac{1}{a})(1+\frac{1}{b})= \frac{a+1}{a} \cdot \frac{b+1}{b}=\frac{ab+a+b+1}{ab}= 1+\frac{2}{ab} \ge k$ Using the Cauchy's...
  46. A

    Finding Maximum Voltage of Resistors

    Homework Statement A 2.44-kΩ and a 4.92-kΩ resistor are connected in parallel; this combination is connected in series with a 1.12-kΩ resistor. If each resistor is rated at 1/2 W, what is the maximum voltage that can be applied across the whole network? Homework Equations P=V^2/Req V=I*R...
  47. I

    Maximum power of circuit with dependent voltage source

    Homework Statement Homework Equations V(oc) = I(sc) * R(th) Kirchoff's voltage law The Attempt at a Solution a) is okay. For part b): After redrawing with the R(th) and V(th) found in part a): Equations of loops: s is I(sc) a is I(left loop) left loop: -8 + a(4000) + (a-s)(4000) = 0 right...
  48. Satvik Pandey

    Maximum extension in spring connecting two masses.

    Homework Statement In the figure shown below all surfaces are friction-less. Find the maximum extension in the spring(in meters) , if the blocks are initially at rest and the spring is initially in its natural length. Details and Assumptions: F=30N k=700N/m m=5kgHomework EquationsThe Attempt...
  49. C

    Critical points and of polynomial functions

    Homework Statement A rectangular region of 125,000 sq ft is fenced off. A type of fencing costing $20 per foot was used along the back and front of the region. A fence costing $10 per foot was used for the other sides. What were the dimensions of the region that minimized the cost of the...
  50. J

    Finding Maximum Power Delivered to Resistor

    Homework Statement Part (a) has already been solved and determined to be 5kΩ, which has been confirmed by the answer key. The answer key also states that the maximum power able to be delivered to Ro is 957 µW, but doesn't give any workings or explanations on how to reach this answer...
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