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Mar
18
comment How do I solve this equation when x approaches zero?
Do you know Taylor series or L"Hospital's Rule? Both would work here...
Mar
9
comment Solve the Lagrangian dual problem
@e2l3n I don't think so, but it's been a while since i looked at these
Mar
4
comment Does the series $\sum_{n=1}^{\infty} \frac{(-1)^n}{n(\sin(n)+2)}$ converge or diverge?
+1, Nice problem :)
Feb
24
comment Is there something wrong with my interchanging of sums and integrals?
@DDaren please see the update - sum is still incorrect
Feb
24
comment Is there something wrong with my interchanging of sums and integrals?
@DDaren yes, it is
Feb
24
comment Is there something wrong with my interchanging of sums and integrals?
@DDaren see no easy way to simplify this, will definitely depend on $A(\cdot)$. Note that it is $$a_1 + 2 a_2 + \ldots x A(x) = A(x) + A(x)-a_1 + A(x)-a_1-a_2 \ldots$$ perhaps this will take you somewhere... not sure how to evaluate this exactly...
Feb
15
comment Probability involving mean time failure
Do you know about exponentially distributed random variables?
Feb
15
comment Is a constant ratio of zero a convergent sum?
@PepperSausage good point but he probably means $$\lim_{r \to 0^+} \sum ar^{k-1} = a...$$
Feb
15
comment Analytical methods for solving polynomial
I don't understand the question. All these methods involve basically factoring the polynomial. What are you asking?
Feb
15
comment Expectation of stochastic differential equation
@user4514 i'm sorry, i scanned the lecture briefly but didn't see it. Can you please let me know where exactly is the counterexample?
Jan
28
comment Find the points where the function is continuous
Notice that $X$ is discrete. Let $x \in X$. What happens at $x$? What about at $x - \epsilon$ if you know $x -\epsilon \not \in X$?
Jan
26
comment Quickest way to determine a polynomial with positive integer coefficients
:-) A hi from one theoretician to another -- in theory beautiful but practically absolutely useless :-) +1
Jan
23
comment Quickest way to determine a polynomial with positive integer coefficients
I see the idea. But how would one practically determine the coefficients given the value on the output, especially in a computerized setting?
Jan
23
comment Quickest way to determine a polynomial with positive integer coefficients
I don't understand. Suppose you call the function and you now know $f(\pi) = 0$. What does that tell you about the coefficients or the degree of $f$?
Jan
13
comment One hundred indistinguishable ants are dropped on a hoop of diameter 1
awesome thanks veryt helpful
Jan
13
comment One hundred indistinguishable ants are dropped on a hoop of diameter 1
But why are the two problems (with bouncing and without boncing) equivalent? I agree if they don't bounce it is trivial, but why are the answers the same for both cases?
Jan
13
comment Graphing a Piecewise Function
i wonder why did someone downvote this... perfectly reasonable to ask a question with own solution posted...
Dec
30
comment Integration with absolute value
@rogerl thanks, fixed - confused sine and cosine
Dec
9
comment Evaluate $\int_{-\infty}^\infty \frac{1}{(x^2+1)^3} dx$
@dustin did not see the tag
Dec
9
comment Integrals over a Surface Using Stokes Theorem
What are your thoughts on the problem? Please explain what you tried and we will be happy to provide hints