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| bio | website | linkedin.com/in/gt6989b |
|---|---|---|
| location | New York, NY | |
| age | 34 | |
| visits | member for | 1 year, 8 months |
| seen | 12 hours ago | |
| stats | profile views | 150 |
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15h |
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Proof for an integral identity +1 - more general than my answer - I didn't want to bother with the integrals :) |
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15h |
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Proof for an integral identity @robjohn thanks, making the change. |
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16h |
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How can I find all the solutions of $\sin^5x+\cos^3x=1$ Substitute $\sin x = \sqrt{1 - \cos x}$ and solve the result in terms of $\cos x$. You could try to reduce $\cos x$ in terms of $\sin x$ as well. |
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16h |
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Comparing $\sqrt{1001}+\sqrt{999}\ , \ 2\sqrt{1000}$ You are asing to show that $\sqrt{x}$ is concave. |
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17h |
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Formula for Sum of Logarithms $\ln(n)^m$ @DonAntonio $\ln \left(n^{\ln n}\right) = \ln n \cdot \ln n = \ln^2 n$ |
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18h |
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Formula for Sum of Logarithms $\ln(n)^m$ Perhaps an idea - not sure if it will help. $$\sum \ln^2 n = \sum \ln n^{\ln n} = \ln \left( \prod n^{\ln n} \right).$$ |
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18h |
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Proof for an integral identity Do you mean $A=B$? Setting $f(x) = f(y) = 1$ as in the above hint yields $AB = A^2$... |
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May 7 |
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Need an algorithm to compute number of elements in sample space @YevgeniyRozhkov for this case, i would condition on $z$ - it's either there or not, and if yes, choose a place for it. Now you reduced it to 2 elements and 2 or 3 places. 2 places are easy and for 3 you condition again. |
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May 7 |
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Evaluate using Riemann sums $\int_a^b \frac{1}{x^2}\mathrm{d}x$ @darenn You're right, looks pretty nasty. |
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May 7 |
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Evaluate using Riemann sums $\int_a^b \frac{1}{x^2}\mathrm{d}x$ What are you asking? How to evaluate the integral using riemann sums? |
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May 7 |
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A problem on calculating rank of a matrix If all except one are $0$, then you get a $0$-matrix with one non-zero diagonal entry, which will have deteminant $0$. |
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May 7 |
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Simple fractions question @user2008436 I see, but a bit weird. My daughter learned solving 1st degree equations in 3rd grade (in the Russian math program), and I've heard the Singapore one is more advanced. Interesting. |
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May 6 |
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Finding the error of the Taylor expansion of $\log(1 + x)$ Write out the first couple of terms in the Taylor expansion of $\log(1+x)$ at $x=0$. Find $R_{0,k}$ and show that $R_{0,k} \to 0$ as $k \to \infty$. |
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May 6 |
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In order to factor we must find its zeros? You can proceed to factor $(x-1)^2-2$ using $a^2-b^2=(a+b)(a-b)$ with $a=x-1$. (What is $b$?) As was pointed out by @TheChaz2.0, factoring and finding zeroes is equivalent. |
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May 3 |
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Numerical estimation of simple integral I got the question. That is the definition of expected value of a function. |
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May 3 |
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Numerical estimation of simple integral You pick the function in such a way that $I = \mathbb{E}[f(U)]$, and then use Monte-Carlo, for example, to compute the expected value... |
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May 3 |
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Considering the linear system Y'=AY To take @julien's answer one step further, note that $AX=\lambda X$ is equivalent to $AX - \lambda X = 0$, which simplifies to $(A-\lambda I)X = 0$, which requires $det(A-\lambda I)=0$ if you want $X \neq 0$... |
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May 3 |
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How to find equation of tangent line to $x^2 = 2y$ at $(-3, 9/2)$ +1, this is clever :) |
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May 3 |
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How to find equation of tangent line to $x^2 = 2y$ at $(-3, 9/2)$ @Steven Please see the edit which explains the concept of the discriminant. |
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May 2 |
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Overlapping Areas If $a+b > c$, by Pigeonhole principle they overlap. Other than that, it is impossible to say - you may have $a = b = c/3$ and they overlap or not overlap, both are possible. Or perhaps I did not understand the problem? |
