Recent content by chwala

  1. chwala

    Undergrad Uniform convergence and pointwise convergence

    I meant for uniform convergence, this must hold ##\lim _{n→∞} sup |f_n (x) - f(x) | =0## and in our case, ##\lim _{n→∞} sup |f_n (x) - f(x) | =1 ≠ 0 ## therefore is not uniform convergent. The concept is dependent on the domain, like for this example if we change the limits slightly to ##x∈...
  2. chwala

    Undergrad Uniform convergence and pointwise convergence

    Thanks @WWGD , getting analysis slowly, in any case analysis is not that difficult as i had earlier thought, ... For uniform convergence to apply, The limit of a sequence (as n approaches infinity) for ##f_n \rightarrow f =0##. In our case, it does not. The limit as n approaches infinity, for...
  3. chwala

    Undergrad Uniform convergence and pointwise convergence

    clearer now, For ##f(x)=x^n ## on ##[0,1]## three cases to consider. Case 1 consider ##0 ≤x <1## ##x^n → 0, ∀ 0 ≤x <1 ## further from my reading as you analyse for ##x## values that are close to 1, the convergence rate slows down. Case 2 ##x=1,## ##1^n → 1## Case 3 ##x=0,## ##0^n → 0##...
  4. chwala

    Solve the given second order differential equation

    Doing some reading ... I want to analyse my problem further by firstly looking at existence and uniqueness. Re-writing it as a first order; ##u_1=u## and ##u_2 =u^{\prime} ## ...i end up with ##u_2^{\prime\prime} = \dfrac{1}{x^2} u_1 - \dfrac{3}{x} u_2## The function is not continuous at...
  5. chwala

    Solve the given second order differential equation

    ok man, I read that. The only thing remaining is for me to get to learn some analysis on this type of problem...
  6. chwala

    Solve the given second order differential equation

    I’ve been exploring the limits of Cauchy–Euler type methods and constructed the following equation: ##4x^5 u'' + 12x^2 u' - 4u = 0## At first glance it resembles an Euler equation, but the usual substitution (u = x^m) does not reduce it to a constant characteristic equation. I’m interested in...
  7. chwala

    Problem involving ordinary differential equation

    ##10^y dy = \dfrac{dx}{x\ln 10}## ##\int 10^y dy = \int \dfrac{dx}{x\ln 10}## ... ##10^y = \ln x +C## ##10^y = \ln (ax)## ##y=\lg(\ln(ax))##
  8. chwala

    Solve the quadratic equation involving sum and product

    for part i. i guess the quadratic equation was not indicated. I will go ahead and finish on that; The quadratic equation will be ##x^2 -p(p^2+3c)x^2-c^3=0##
  9. chwala

    Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}##

    a different line for ##\tan 4S## ##\tan (4S)= \tan (2S +2S) = \dfrac{\tan 2S + \tan 2S}{1 - \tan^2 (2S)}## ##\tan (2S) = \dfrac{5}{12}## therefore, ##\tan 4S= \left[ \dfrac{\dfrac{5}{12} + \dfrac{5}{12}}{1-\left[\dfrac{5}{12}\right]^2}\right]## ##\tan 4S=...
  10. chwala

    Prove that ## 4\tan^{-1}\left[\dfrac{1}{5}\right]- \tan^{-1}\left[\dfrac{1}{239}\right]= \dfrac{π}{4}##

    I note that in my proof, i did not have the ##4S## and instead worked with ##S## ... that was wrong. Your working clearly shows that error on my part. Cheers.
  11. chwala

    Thanks @neilparker62

    Thanks @neilparker62
  12. chwala

    @neilparker62 , mate, let me just go with what is there, i fully understand it if there is no...

    @neilparker62 , mate, let me just go with what is there, i fully understand it if there is no official letterhead. Any letter will do. Cheers and thanks to reach out again...
  13. chwala

    @neilparker62 I will appreciate it, ...not yet gotten any reference... the reference am assuming...

    @neilparker62 I will appreciate it, ...not yet gotten any reference... the reference am assuming will have letterhead physicsforums (an official one) ... other than that be blessed 🙌 brother...