Recent content by MIB

  1. M

    Learning mathematics but need to know physics

    I teach myself mathematics, but I want also to broaden my knowledge with some physics, which I think will enhance my intuition for different things in mathematics. The problem is that it seems I know nothing about physics. So I want you to recommend me which book(or books) must I read to develop...
  2. M

    Book on Probability: Learn from Elementary to Advanced

    Please , I want you to recommend me to a book on probability , I a have never read a probability book , or have a good background , I only Know what are probability measures , some theorems concerning it . I want a book that take me from the elementary probability , to advanced probability...
  3. M

    I think there is some thing wrong

    OK I restated it as following let f : (a,b) → ℝ be a differentiable function , suppose that f' is bounded , and that f has a root r in (a,b) . suppose that for x ≠ r , Jx denote the open interval between x and r , where if f(x) > 0 then f is convex on Jx , and if f(x) < 0 then f is concave on...
  4. M

    I think there is some thing wrong

    I know it can be very hard to think an example where the derivative vanishes at a point which is not a root , and I think it is impossible the problem is that it says " for any x0 in (a,b) the Newton sequence converges to a root where x0 is it initial point " , and then this wrong ,because the...
  5. M

    I think there is some thing wrong

    I think we must replace "f' is bounded on (a,b)" by "f' is non-zero throughout (a,b)"
  6. M

    I think there is some thing wrong

    I think there is some thing wrong in this exercise which I met by chance in a book of Calculus and analysis while looking for rigorous definition for angle , it says let f : (a,b) → ℝ be a differentiable function , suppose that f' is bounded , and that f has a root r in (a,b) . suppose...
  7. M

    Why there is no answer when negative value is being square root?

    to our intuition we see that there is no number that if we multiplied by itself will be negative , since if it is negative then squaring it will result in a positive number , and the same for positive numbers , precisely we see that from the properties of the order field of real numbers that if...
  8. M

    Rigorously Proving Direct Proportionality: Let's Find Out!

    ok must I begin know to prove the generalized theorem with this background in Mathematics ?
  9. M

    Rigorously Proving Direct Proportionality: Let's Find Out!

    no , I don't know it , but if I knew , I would put X as the set of 1/Q , where Q is a natural number and the number 0 , and the accumulation point is 0
  10. M

    Rigorously Proving Direct Proportionality: Let's Find Out!

    yes , In fact I am using this to prove the uniqueness of the representations of functions as a power series , I yes I know about power series and series of functions and sequences of functions ... etc
  11. M

    Rigorously Proving Direct Proportionality: Let's Find Out!

    Is that true ? Let be \Sigma_{n=1}^{\infty} a_n a series in ℝ .Suppose that \Sigma_{n=1}^{\infty} a_n is absolutely convergent . Suppose that for each Q \in N , \Sigma_{n=1}^{\infty} \frac{a_n}{Q^n} is convergent and \Sigma_{n=1}^{\infty} \frac{a_n}{Q^n} = 0.Then a_n = 0 for all n \in N...
  12. M

    Why subsitution method for integration always work ?

    why substitution method for integration always work ? Why can we completely treat dx and du known in substitution method completely like differentials even if we don't have ∫f(g(x))g'(x) dx , i.e : why we can substitute x in terms of u and dx in terms of du . thanks
  13. M

    Understanding the Implication in the Proof of a Theorem

    another question please , when I want to prove statements like that \lim_{x \to a} f(x) = \lim_{h \to 0} f(a+h) MUST I prove the two following statements or one of them is enough 1 - Assume that \lim_{x \to a} f(x) = L , and peove that given ε > 0 , there exists δ > 0 such that ...
  14. M

    Understanding the Implication in the Proof of a Theorem

    IS This argument is right
  15. M

    Understanding the Implication in the Proof of a Theorem

    Now I think that all what I say in the end was useless but I am not sure , the definition says that if a function f is defined on some open containing a except possibly at a , then we write \lim_{x \to a} f(x) = L if for every ε > 0 , there exists positive number δ such that if...
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