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2d
comment Differential Equation - Water evaporation
Sure, we don't really need calculus. The surface area is constant, so the rate of evaporation is constant, we are dry $30$ days after the experiment starts.
2d
comment Given an unfilled pmf, How to compute the Correlation coefficient?
There is no density function, the distribution is discrete. Please see the answer for a detailed beginning to the calculations.
2d
answered Given an unfilled pmf, How to compute the Correlation coefficient?
2d
comment Given an unfilled pmf, How to compute the Correlation coefficient?
You have all the values. The given ones add up to $1$ so all other entries are $0$.
2d
comment Probability of ultimate extinction? Need to show that an infinite series is less than $1$
One can get a closed form.
2d
comment How to take apart a characteristic polynomial
Your second factor is not right. One can hope for a rational root, and then by the Rational Roots Theorem the only possibilities are $\pm 1, \pm 2,\pm 4$.
2d
comment Proving limit through definition
Your $\delta$ is fine. Even $\min(1,5\epsilon/2)$ would woek. Their $\min(1,\epsilon)$ is "worse" in a sense, more demanding. But in a sense better, they did not go to any effort to get an "optimal" $\delta$, which is in any case not asked for.
Dec
16
awarded  Enlightened
Dec
16
answered Find the least positive integer $x$ that satisfies the congruence $90x\equiv 41\pmod {73}$
Dec
16
comment Integration Question - Not sure how to approach
@@Integrator: I have written out the requested answer. Without the interaction with OP it loses interest. I think for the other problem you mentioned, the comments are even less worth turning into an answer. They were useful to OP at the time, but that's all. If you disagree please feel free to answer.
Dec
16
answered Integration Question - Not sure how to approach
Dec
16
comment Finding number of integral solutions
The general idea works, a little tedious. Some are left out like $110, 7,1,1$ and others like that. And they may really mean integers, as in allowing negatives.
Dec
16
comment mean, standard deviation
Yes, thank you! Distressing to have this happen in such a short piece of text.
Dec
16
revised mean, standard deviation
edited body
Dec
16
answered mean, standard deviation
Dec
16
reviewed Leave Open mean, standard deviation
Dec
15
comment Series and Sequences Train Question
You are welcome. It is a puzzle, So this is in the AP GP chapter? One can interpret, Galileo style, constant acceleration as meaning that the intervals covered in successive equal time chunks form an AP, but that is a more sophisticated approach than the one I took.
Dec
15
answered Sum of uniformly distributed random variables in a given range
Dec
15
revised Properties of $ f(k) =\int_0^k \frac{3+\sin(x)}{1+x^2}dx$
added 84 characters in body
Dec
15
answered Properties of $ f(k) =\int_0^k \frac{3+\sin(x)}{1+x^2}dx$