Recent content by topengonzo

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    Proving (a+1/a)^2 + (b+1/b)^2 ≥ 25/2 Given a+b=1

    I just have to prove ab + 2/ab -4 >= 25/2 when a+b=1 How to do it without Lagrange
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    Proving (a+1/a)^2 + (b+1/b)^2 ≥ 25/2 Given a+b=1

    the equations are: 2(a^4) - λ (a^3) -2 = 0 2(b^4) - λ (b^3) -2 = 0 a+b-1=0 I can solve by trial and error to get a=b=0.5 but what if there is another root for these equations
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    Proving (a+1/a)^2 + (b+1/b)^2 ≥ 25/2 Given a+b=1

    I differentiated it with respect to a and i get the equation a - 1/(a^3) - (1-a) + 1/(1-a)^3 = 0 which I can't solve :S
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    Proving (a+1/a)^2 + (b+1/b)^2 ≥ 25/2 Given a+b=1

    Homework Statement How to prove (a+1/a)^2 + (b+1/b)^2 >= 25/2 given that a+b=1 and a,b positive Homework Equations The Attempt at a Solution I tried replacing b with 1-a but I get 6th degree a which I don't know how to find inequality for. Since a and b are perfect symmetric in...
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    How can I prove this inequality

    Shouldn't I check at x=y and also at the boundaries that is x=0,y=10 and x=10,y=0?
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    Few suggestions about cauchy inequality

    How to prove it?
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    Few suggestions about cauchy inequality

    Your right. Rereading the lecture, they mentioned that that a1,..,an and b1,...,bn are in descending order and they are all positive.
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    Is my solution correct and is there another way to solve it?
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    \sum_{r=k+1}^{n+1} \frac {1} {(r-1)!} - \sum_{r=k+1}^{n+1} \frac {1} {(r)!} YOUR RIGHT! it becomes simply \frac {1} {(k)!} - \frac {1} {(n+1)!} Just 1 final question? I take lim as n tends to infinity of my answer so I get that the infinite sum of all terms after ak/k! is...
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    \sum_{r=k+1}^{n+1} \frac {r-1} {(r)!} < \frac 1 {k!} Is this correct? \sum_{r=0}^{inf} \frac {r-1} {(r)!} = e-e=0 And then I take out term from 0 to k?
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    I think that your previous answer using series will solve it. I am thinking of putting \sum_{r=k}^n \frac r {(r+1)!} < \frac 1 {k!} and I use the poisson distribution series to prove = 1/k! and thus the sum of any finite terms of the series is < 1/k! Am I correct?
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    Few suggestions about cauchy inequality

    As I can see from the formula of cauchy inequality: (a1^2+a2^2+...+an^2)^1/2 . (b1^2+b2^2+...+bn)^1/2 >= a1b1+a2b2 + ... + anbn Can I conclude from the above formula that: (a1+a2+...+an)^1/2 . (b1+b2+...+bn)^1/2 >= (a1b1)^1/2 + (a2b2)^1/2 +...+ (anbn)^1/2 by setting a1,...,an =...
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    This is not the question of my homework. I will write it here down to show you that I am doing an effort and what I am asking will lead me to the answer. Question: Prove every positive rational number x can be expressed in ONE way in the form x= a1 + a2/2! + a3/3! + ... + ak/k! where...
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    Yes the second one you wrote is what i exactly mean. How do I prove it? Also I think if i set n -> infinity (find lim at infinity), I would get = instead of < . Am I correct?
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    Solving Summation Using Induction: 1/((k-1)!(k+1)) < 1/k!

    n is induction variable and base term is n=k
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