Exponential Definition and 1000 Threads

  1. F

    I Exponential of hypercomplex numbers

    The exponential of a complex number is a complex number. Does this extent to the quaternions and the octonions? Does the exponential of a quaternion give a quaternion? Does the exponential of an octonion give an octonion? Thanks.
  2. W

    I How Is the Exponential Map Defined for Lie Groups Without a Metric?

    I’ve read about the exponential map that for Lie groups the exponential map is actually the exponential function. But the exponential map is based on the geodesic ODE, so you need Christoffel symbols and thus the metric. But usually nobody gives you a metric with a Lie group. So how can I get...
  3. Prof Sabi

    Integration of an exponential function

    How to Integrate it::: ∫e^(ax²+bx+c)dx Or in general e raised to quadratic or any polynomial. I am trying hard to recall but I couldn't recall this integration. I tried using By-parts but the integration goes on and on.
  4. F

    Solving for time in an exponential equation

    Homework Statement In my book, there is a formula that gives the amount (in grams) of Radium in a jar after t years (100 grams were initially stored): R = 100⋅e-0.00043⋅t The book asks me to sketch the graph of the equation. I decided to find a point where the time elapsed equals the...
  5. Phylosopher

    I Is the exponential function, the only function where y'=y?

    Hello,I was wondering. Is the exponential function, the only function where ##y'=y##. I know we can write an infinite amount of functions just by multiplying ##e^{x}## by a constant. This is not my point. Lets say in general, is there another function other than ##y(x)=ae^{x}## (##a## is a...
  6. wolf1728

    I What is the exponential decay equation for a bouncing ball?

    This is not a physics question. Each time a ball bounces it will bounce to, let's say 75% of its previous height. (I am not interested in the time, energy or velocity, of the ball.) So if we drop it from 100 cm it will bounce back up to 75 cm, and on the next bounce it goes up to 56.25 cm and...
  7. S

    Sum of (n+1) terms in exponential series

    Homework Statement S = 1+ x/1! +x2/2! +x3/3! +...+xn/n! To find S in simple terms. Homework Equations None The Attempt at a Solution I tried with Taylor's expansion, coshx and sinhx expansions. But cannot see consequence.
  8. CalcExplorer

    A How to Convert a Complex Logarithm to a Complex Exponential

    Okay, so I'm working with a rather frustrating problem with a calculus equation. I'm trying to solve a calculus equation which I conceptualized from existing methods involving complex number fractal equations. I'm very familiar with pre-calculus, while being self-taught in portions of calculus...
  9. rocdoc

    I Decomposing a Certain Exponential Integral

    There is nothing wrong with the well known $$e^{i\theta}=\cos\theta+i\sin\theta$$ for real ## \theta## but what about $$\int_{-\infty}^\infty~e^{i\theta(p)}\mathrm{d}p=\int_{-\infty}^\infty~\cos\theta(p)\mathrm{d}p+i\int_{-\infty}^\infty~\sin\theta(p)\mathrm{d}p$$ I have been trying to use...
  10. Y

    MHB Exponential Functions Problem, find k and a in f(x)=ka^(−x)

    Hello all, I am trying to solve the following problem: In the given graph, we see the function: \[f(x)=ka^{-x} , x\geq 0\] 1) Find k and a 2) Find x1 3) Show that an increase of 2 units in x brings a 50% reduction in the value of the function f. I have tried solving it, but taking two...
  11. Jakub

    Bi-exponential function fitting in Origin Lab SW

    I can't understand the exponential function fit for this set of data works well: ExpDec2 exponential function fit 0 3,04 10 2,77 20 2,52 30 2,27 40 2,09 50 1,92 60 1,75 70 1,62 80 1,51 90 1,43 100 1,36 110 1,29 120 1,24 130 1,19 140 1,14 150 1,09 160 1,05 170 1,02 180 0,99 190 0,97 200 0,95 210...
  12. E

    I Probability density of an exponential probability function

    I have a model where the probability is spherically symmetric and follows an exponential law. Now I need the probability density function of this model. The problem is the singularity at the origin. How can I handle this? P(r) = ∫p(r) dr = exp(-μr) p(r) = dP(r)/(4πr²dr) One way I tried to...
  13. opus

    B Exponential Growth: Modeling growth in months vs years

    Say I have a function that represents the population growth of a certain country that can be written as ##f\left(x\right)=1.25\left(1.012\right)^t##, where t is in years. I can graph this function and it will look a certain way exponentially. I've looked at a ton of examples, and they're all...
  14. Peter Alexander

    Fourier transform of exponential function

    1. The problem statement, all variables, and given/known data Task begins by giving sample function and a corresponding Fourier transform $$f(t) = e^{-t^2 / 2} \quad \Longleftrightarrow \quad F(\omega) = \sqrt{2 \pi} e^{-\omega^2 / 2}$$ and then asks to find the Fourier transform of $$f_a(t) =...
  15. F

    MHB Exponential Equations solve 27^x=1/√3

    I'm taking an online class and I was doing some very simple exponential equations when this was thrown at me, and I have no clue how to solve it. 27^x=1/√3
  16. A

    Exponential decay of a pendulum oscillation amplitude

    Homework Statement I found an answer on the internet for this problem, but I'm not sure on one of the steps. The solution says, "Take ln of both sides to get rid of Ae. If we do that, then the right side will be ln(Ae^t/T). I don't see how using ln will get rid of Ae? Homework Equations Refer...
  17. D

    MHB How Do You Calculate the Real and Imaginary Parts of \( e^{e^z} \)?

    Let f(z) = $e^{e^{z}}$ . Find Re(f) and Im(f). I don't know how to deal with the exponential within an exponential. Does anybody know how to deal with this?
  18. M

    MHB Exponential distribution - inequality

    Hey! :o We consider the exponential distribution. I want to show that $$\mathbb{P}\left (\left |X-\frac{1}{\lambda}\right |\leq \lambda \right )\geq \frac{\lambda^4-1}{\lambda^4}$$ I have shown so far that \begin{align*}\mathbb{P}\left (\left |X-\frac{1}{\lambda}\right |\leq \lambda \right...
  19. R

    B Exponential decay convolved with Gaussian

    Hello all, I have a data which look like reversed exponentially modified Gaussian (EMG) function and interested to fit the data with with reversed EMG function. After searching on internet I found the EMG function, which is given below...
  20. M

    MHB Proving Limits of Exponential Series at Infinity

    Hey! :o I want to show that $\displaystyle{\lim_{x\rightarrow \infty}\frac{e^x}{x^{\alpha}}=\infty}$ and $\displaystyle{\lim_{x\rightarrow \infty}x^{\alpha}e^{-x}=0}$ using the exponential series (for a fixed $\alpha\in \mathbb{R}$). I have done the following: $$\lim_{x\rightarrow...
  21. Pushoam

    Determinant of exponential matrix

    Homework Statement Homework EquationsThe Attempt at a Solution [/B] Det( ## e^A ## ) = ## e^{(trace A)} ## ## trace(A) = trace( SAS^{-1}) = 0 ## as trace is similiarity invariant. Det( ## e^A ## ) = 1 The answer is option (a). Is this correct? But in the question, it is not...
  22. J

    MHB Integral of Rational Exponential

    Hi, I'm new to this forum. This semester I took Calculus I and just took the final yesterday. There were a few questions that were unexpected that I didn't know how to handle. This integral has got me stumped.\int_{0}^{1} e^{x}/(1 + e^{2x}) \,dx The techniques I know at this point include u...
  23. M

    Getting the Horizontal Asymptotes

    Homework Statement Homework EquationsThe Attempt at a Solution I understand there is no vertical asymptotes and can usually get the horizontal ,but can't understand with the exponential.
  24. F

    Simplification of a complex exponential

    Homework Statement Is there a way to simplify the following expression? ##[cos(\frac {n \pi} 2) - j sin(\frac {n \pi} 2)] + [cos(\frac {3n \pi} 2) - j sin(\frac {3n \pi} 2)]## Homework Equations ##e^{jx} = cos(x) + j sin(x)## The Attempt at a Solution ##cos(\frac {n \pi} 2)## and...
  25. M

    MHB Can we somehow modify the Lagrange form to get a tighter bound? (Curious)

    Hey! :o I am looking at the following: Show that $\displaystyle{\text{exp}(1)=\sum_{k=0}^{\infty}\frac{1}{k!}=e}$ with $\displaystyle{e:=\lim_{n\rightarrow \infty}\left (1+\frac{1}{n}\right )^n}$. Hint: Use the binomial theorem and compare with the partial sum $s_n$ of the series...
  26. M

    MHB Normal and exponential distribution

    Hey! :o I am looking at the following: 1) A machine produces $100$ gram chocolate. Due to random influences, not all bars are equally heavy. From a long series of observations it is known that the mass X of a chocolate is distributed normally with parameters $\mu = 100$g and $\sigma = 2.0$g...
  27. A

    Solution of an exponential equation

    Homework Statement I am trying to solve an equation. 128^b - 127^b = 147.058. Homework EquationsThe Attempt at a Solution I have tried numerical methods like Bisection method and Newton-Raphson, but I need analytical solution. Thank you.
  28. VSayantan

    Trace of the Exponential of a Square Matrix

    Homework Statement Find the trace of a ##4\times 4## matrix ##\mathbb U=exp(\mathbb A)##, where $$\mathbb A = \begin {pmatrix} 0&0&0&{\frac {\pi}{4}}\\ 0&0&{\frac {\pi}{4}}&0\\ 0&{\frac {\pi}{4}}&0&0\\ {\frac {\pi}{4}}&0&0&0 \end {pmatrix}$$ Homework Equations $$e^{(\mathbb A)}=\mathbb P...
  29. ElPimiento

    Coefficients for an exponential Fourier Series

    I'm kinda just hoping someone can look over my work and tell me if I'm solving the problem correctly. Since my final answer is very messy, I don't trust it. 1. Homework Statement We're asked to find the Fourier series for the following function: $$ f(\theta)=e^{−\alpha \lvert \theta \rvert}}...
  30. B

    Matrix Exponential Homework: Eigenvalues & Eigenvectors

    Homework Statement Show that if ##λ##and ##V ## are a pair of eigenvalue and eigenvector for matrix A, $$e^Av=e^λv$$ Homework Equations ##e^A=\sum\limits_{n=0}^\infty\frac{1}{n!}A^n## The Attempt at a Solution I don't know where to start.
  31. J

    Exponential forcing function to an RL circuit -- poles & zeros

    For reference: Engineering Circuit Analysis, Hayt & Kemmerly, 4th ed, 1986, page 345. Given a series RL circuit, the phasor current is I(s) = Vm/(R+sigma L), where S = sigma, w (omega) = 0. Thus we are dealing with only a exponential forcing function. Obviously I(s) goes to zero as sigma...
  32. B

    Solutions to Equations Involving Exponential and Trig Functions

    Homework Statement Show that ##e^x = x## does not have any solutions, and show that ##\sec x = e^{-x^2}## has only one solution. Homework EquationsThe Attempt at a Solution Here is my proof of the first proposition: Since ##e^x## is concave up on ##\Bbb{R}##, it must lie above all of its...
  33. T

    B What are the equations for the quadratic and power laws in unstable systems?

    http://www.nat.vu.nl/~tvisser/nonexponential.pdf I always thought that an unstable system will decay exponentially but I recently learned that it obeys the quadratic law in the short time and power law in the long time. Can somebody tell me the equation that governs the quadratic law and power law?
  34. J

    I Proving Matrix Exponential Theorem: Unipotent & Nilpotent

    Hi, I'm kind of stuck with this theorem stating that: if A is an unipotent matrix, then exp(log A) = A and also if X is nilpotent then log(exp X) = X Does anyone know any good approaches to prove this? I know that for unipotent A, logA will be nilpotent and that for nilpotent X, exp(X)...
  35. O

    Exponential Distribution, Mean, and Lamda confusion

    Homework Statement Accidents at a busy intersection follow a Poisson distribution with three accidents expected in a week. What is the probability that at least 10 days pass between accidents? Homework Equations F(X) = 1- e-λx μ = 1/λ The Attempt at a Solution Let x = amount of time between...
  36. J

    Analytic Integration of Function Containing the Exponential of an Exponential

    Homework Statement Can this function be integrated analytically? ##f=\exp \left(-\frac{e^{-2 \theta } \left(a \left(b^2 \left(e^{2 \theta }-1\right)^2 L^2+16\right)-32 \sqrt{a} e^{\theta }+16 e^{2 \theta }\right)}{b L^4}\right),## where ##a##, ##b## and ##L## are some real positive...
  37. E

    B Logarithmic growth vs exponential growth

    From the book Calculus made easy: "This process of growing proportionately, at every instant, to the magnitude at that instant, some people call a logarithmic rate of growing." From Wikipedia: "Exponential growth is feasible when the growth rate of the value of a mathematical function is...
  38. S

    MHB Exponential Equation: If X is one more than twice Y, what is the value of X?

    The square of X is equal to 4 times the square of Y. If X is one more than twice Y, what is the value of X?
  39. M

    MHB How can I solve more complex exponential equations?

    I can solve equations like 4^(x) = 16 or 5^(x + 1) = 25. However, there are exponential equations that a bit more involved. The following equation has two exponentials on the left side. Solve for x. 5^(x - 2) + 8^(x) = 200
  40. onemic

    Exponential and logarithmic Equation Problems

    Homework Statement Evaluate each of the following expressions without using a calculator. 1) log216√8Solve for the unknown value in each of the following equations without using a calculator. 2) 3(x+4)−5(3x)=684 3) 7(42x)=28(4x) Homework Equations Exponent law for multiplication The...
  41. C

    I Exponential Distribution Question

    Hi all, Can anyone teach me this problem ? Thanks The life of a tiger is exponentially distributed with a mean of 15 years.If a tiger is 10 years old, what is the expected remaining life of the tiger? A 5 years B 10 years C 15 years D Longer than 15 years
  42. Jehannum

    I Exponential decay: I need an expression for N at time t

    I have a large quantity N, which starts off equal to a determinable value N0. Over a short time ∆t, the value of N changes by -∆t*(B*N - C) where B and C are determinable constants. Am I correct in thinking I can turn this into: dN/dt = -(B*N - C) How do I get this into a formula for N at...
  43. Alettix

    Exponential Forcing Differential Equation

    Homework Statement Solve ## \frac{d^2y}{dt^2} + \omega^2y = 2te^{-t}## and find the amplitude of the resulting oscillation when ##t \rightarrow \infty ## given ##y=dy/dt=0## at ##t=0##. Homework EquationsThe Attempt at a Solution I have found the homogenious solution to be: ##y_h = A\cos\omega...
  44. T

    I Why Does Unstable Particle Decay Follow an Exponential Curve?

    Given that an unstable particle has a constant probability of decaying per unit time, why is it said that its chance of surviving falls exponentially?
  45. Eclair_de_XII

    How to prove that two exponential terms are congruent to 7?

    Homework Statement "Prove: ##∀n∈ℕ,7|[3^{4n+1}-5^{2n-1}]##" Homework EquationsThe Attempt at a Solution (1) "We take the trivial case: ##n=1##, and notice that ##3^5-5=238## and ##7|238## because ##7⋅(34)=238##." (2) "Now let ##n=k## for some ##1<k∈ℕ##. Then we assume that...
  46. M

    MHB How to change the subject when exponential is involved

    It's been a long time since I've worried about this - but could someone help me make Pr(x) the subject (I can't remember if it's possible, if it's not, I'd love a brief explanation): T = S [(1-Pr(x))^N] + Pr(x) Thanks in advance!
  47. P

    A Closed form for series over Exponential Integral

    Is there a closed form for the constant given by: $$\sum_{n=2}^\infty \frac{Ei(-(n-1)\log(2))}{n}$$ (Where Ei is the exponential integral)? Could we generalize it for: $$I(k)=\sum_{n=2}^\infty \frac{Ei(-(n-1)\log(k))}{n}$$ ? My try: As it is given that k will be a positive integer, I have...
  48. Z

    Exponential of hermitian matrix

    Homework Statement Let A be a Hermitian matrix and consider the matrix U = exp[-iA] defined by thr Taylor expansion of the exponential. a) Show that the eigenvectors of A are eigenvectors of U. If the eigenvalues of A are a subscript(i) for i=1,...N, show that the eigenvalues of U are...
  49. F

    MHB Find x in Exponential Equation: 2^x=8x

    Find x, if 2^x =8x.
  50. chwala

    How can we prove ##e^{ln x}= x## and ##e^-{ln(x+1)}= \frac 1 {x+1}##?

    Homework Statement they say 1. ##e^{ln x}= x ## and 2.##e^-{ln(x+1)}= \frac 1 {x+1}## how can we prove this ##e^{ln x}= x ## and also ##e^-{ln(x+1)}= \frac 1 {x+1}##? Homework EquationsThe Attempt at a Solution let ## ln x = a## then ##e^a= x, ## a ln e= x,## →a= x, where ## ln x= x
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