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  1. T

    Inequalities 🥲

    You may proceed to simplify the induction hypothesis to make it easier to do the induction step. So your induction hypothesis assume k^{k+1}>(k+1)^k is equivalent to \textstyle(1+\frac{1}{k})^k<k. You can see why by dividing by k^k. Now in order to do the induction step, one only needs to...
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    binomial limit

    \text{You can generalise it more to }\forall\alpha,\beta\in\Bbb R,\lim\limits_{n\rightarrow\infty}\left(\prod_{r=0}^n{n\choose r}\right)^\frac{1}{(n+\alpha)(n+\beta)}=\sqrt e I rewrote the proofs for this more general formula and it is now at...
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    Trigonometric Equations

    Yes. There are a lot of old threads with matters not yet resolved which are still worth exploring. Some old threads are closed like the old integration marathons, but most are still open.
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    Trigonometric Equations

    I checked the difference in answers on wolframalpha So it looks like you have the same for when x>0. But what about if x<0? Then you can also have (-5\sqrt{5},2(\pi n-\tan^{-1}(2+\sqrt{5}))),n\in\Bbb Z
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    Trigonometric Equations

    I put them into wolframalpha and got assuming you only want the real solutions. There are complex ones too but I left them out.
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    Limit with binomial Coefficients

    Use blah blah instead of $blah blah$ to avoid Invalid Equation message. \displaystyle \lim_{n\rightarrow \infty} n^{-2}\cdot \sum^{n}_{k=0}\ln\bigg(\binom{n}{k}\bigg) Put into wolframalpha and you get 0.5
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    Irrational Integration

    You know that in this forum for LaTeX you use blah blah instead of $blah blah$ otherwise you get Invalid Equation message Anyway I fixed it for you. Here were your questions: \int\frac{\sqrt{9x^2+4x+6}}{8x^2+4x+6}dx \text{Evaluation of }\int\frac{x^2(x\sec x+\tan x)}{(x\tan x-1)^2}dx Then...
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    binomial limit

    \text{By the way did you know that for any real number }\alpha, \lim_{n\rightarrow\infty}\left(\prod_{r=0}^n{n\choose r}\right)^\frac{1}{n(n+\alpha)}=\sqrt e\ ?
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    binomial limit

    I might look at that later but if we call your way Method 4 then there is yet another method using integration. Method 5 \text{If }\textstyle p_n=\ln\prod_{r=0}^n{n \choose r}=\ln\prod_{r=1}^nr^{2r-n-1}=\sum_{r=1}^n(2r-n)\ln\frac{r}{n}+n\ln n-\ln n! \text{noting that...
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    binomial limit

    Here is another method using the Stolz–Cesàro theorem. It starts the same as the first method but then goes in a completely different direction, nevertheless ending up at the same answer. Method 3. \begin{aligned}\ln\lim_{n\rightarrow\infty}\left(\prod_{r=0}^n{n\choose...
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    Integral calculus

    Solutions. 8. Solve the equation from the areas of the 2 trapezia (5+2)(10)/2=(6+4)(k-4)/2\Rightarrow k=11\therefore D. You can also work it out using the integrals of the lines, but using the areas of the trapezia is easier. 10. \pi\int_0^{64}((2\sqrt...
  12. T

    Integral calculus

    You can put them all into wolframalpha to get the answers 8. D 10. D 13a. i. 2x^6+\frac{7x^4}{4}-9x+c 13 a ii 8\sqrt x+c 13b 12.5 13e \frac{\pi}{30} 14 a \frac{10}{3} 14b i \frac{32x}{(5x^2+1)^2} 14b ii \frac{x^2-3}{10x^2+2}+c
  13. T

    How would you do this ?

    So to do the actual question: a. \text{Base Step: } 2^1=2>1\text{ but in this case I would also check }2^2=4>2\text{ and you will see why in the induction step} \text{Induction Step:} \text{If for }k>1, 2^k>k\text{ then } 2^{k+1}=2^k\cdot2>k\cdot2=k+1+k-1>k+1\text{ since }k>1 Hence by the...
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    How would you do this ?

    Yes I think it should be less than or equal to, equal in the case of n=1. If you allow n to be a real number you can get it to be less than 1 but the maximum is \sqrt[e]{e} so for positive integers the maximum is \sqrt[3]{3}\approx1.44 and minimum is 1. So a tighter bound for positive integers...
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    binomial limit

    There is another way to do it using Stirling's formula So here is Method 2: \text{If }p(n)=\left(\prod_{r=0}^n{n \choose r}\right)^\frac{1}{n(n+1)}\text{ then }p(n)^{n(n+1)}=p(n-1)^{n(n-1)}\cdot\frac{n^n}{n!}. \text{ If }L=\lim_{n\rightarrow\infty}p(n)\text{ then }...
  16. T

    binomial limit

    The gamma function is just a continuous version of factorial and the digamma and trigamma just come from the derivatives. The hardest function that appeared was the hyperfactorial but I got rid of it pretty quickly by using l'Hôpital's rule. That's a nifty rule to use in limits - even for much...
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    binomial limit

    If I can do it then anyone can do it.
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    Prove that there is no greatest even integer

    If you assume if it exists then it is 2k for an integer k. But then I'd be more inclined just to add 2. So now 2k+2=2(k+1) is a bigger even integer - contradiction \therefore there is no biggest even integer.
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    Can anyone please provide some feedback on my proof

    might be easier to use mod 4 arithmetic for n^2=4m+3 If 4 divides n^2-3 then there exists an integer m such that n^2-3=4m\therefore n^2=4m+3 4m+3\equiv3(\mod 4) If n is an integer then there are 4 cases for n^2 n^2\equiv(0(\mod 4))^2=0(\mod 4) n^2\equiv(1(\mod 4))^2=1(\mod 4)...
  20. T

    binomial limit

    This is how I did it without wolframalpha. First use a logarithm to turn the product into a sum so it is easier to deal with. Thereafter it is a matter of simplifying the limit as much as possible. Method 1 (see more methods in subsequent posts)...
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