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location Minneapolis, MN
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visits member for 3 years, 1 month
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I have a Ph.D. with a minor in mathematics and a major in statistics.


2d
revised Can't understand a step in the advanced calculus book by thomas P. Dence
typo
2d
answered Solving Trigonometric Problems Like These
2d
comment Euclid's proof of the infinitude of primes to prove this question
@daniel : Thank you.
2d
comment What does taking the $n^{\text{th}}$ root of a complex number geometrically mean?
You should bear in mind the geometric meaning of multiplication of complex numbers in thinking about this. That's the place to start.
2d
revised When is the earliest large prime gap also the latest large prime gap?
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2d
revised Applications of calculus
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2d
revised Composition of injective linear maps.
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2d
revised Logarithm Equality.
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2d
revised Probability of multiple variables, geometric distribution?
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2d
comment Prove that if $X \sim N(\mu, \sigma^2)$, then $X \sim \mu + \sigma N(0, 1)$
oh : I had the two distributions switched around: $N(\mu,\Sigma)$ where $N(0_n,I_n)$ should be and vice-versa.
2d
revised Prove that if $X \sim N(\mu, \sigma^2)$, then $X \sim \mu + \sigma N(0, 1)$
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Jul
19
revised How prove for any postive integer $k$,there exsit positive integer $a_{k}$,such $29^k\mid(a^3_{k}-9)$
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Jul
19
comment Prove that if $X \sim N(\mu, \sigma^2)$, then $X \sim \mu + \sigma N(0, 1)$
It may be that the reason this was put on hold is that it is phrased somewhat like a homework problem but doesn't share the poster's thoughts on how to solve it nor on where the poster got stuck while making the attempt.
Jul
19
comment Prove that if $X \sim N(\mu, \sigma^2)$, then $X \sim \mu + \sigma N(0, 1)$
@Did : I missed the square root. I've added it now.
Jul
19
revised Prove that if $X \sim N(\mu, \sigma^2)$, then $X \sim \mu + \sigma N(0, 1)$
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Jul
19
comment The second derivative of g(t)= f(x(t), y(t))
I've cleaned up your MathJax usage quite a bit. But notice that I haven't written $\dfrac{\partial^2 f}{\partial x\,\partial y}$. It is possible to do that.
Jul
19
revised The second derivative of g(t)= f(x(t), y(t))
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Jul
19
comment On which occasions will the intelligent layperson fail to recognize a mathematics problem?
@Silynn : If it is easier, that doesn't mean it is as informative.
Jul
19
comment Euclid's proof of the infinitude of primes to prove this question
A student once suggested to me that the same argument that proves $p_1\cdots p_n+1$ is prime would do the same for $p_1\cdots p_n-1$, and thereby prove that infinitely many twin primes exist. But that conjecture remains open.
Jul
19
comment Euclid's proof of the infinitude of primes to prove this question
...then what you get is always prime. Obviously if one could prove that, then that would entail the infinitude of primes, so it's tempting to think that that is indeed what was proved. But there are counterexamples, e.g. $2\times3\times5\times7\times11\times13 +1 = 59\times509$. As soon as a student learns of these counterexamples, the student might then conclude (erroneously!) that Euclid's proof was mistaken.