Stephen Donovan's user avatar
Stephen Donovan's user avatar
Stephen Donovan's user avatar
Stephen Donovan
  • Member for 3 years, 1 month
  • Last seen this week
  • Raleigh, NC, USA
10 votes

Why aren't $\int_0^\pi\int_{-1}^1e^rdr\,d\theta$ and $\int_0^{2\pi}\int_0^1e^rdr\,d\theta$ equal? Doesn't this violate the Change of Variables thm?

10 votes
Accepted

Solve in 75 seconds: $\displaystyle{\iiint_{\Omega} {\dfrac{(3x + y − 4)^2}{9x^2 + y^2 + z^2 − 18x − 2y + 10}} \,dz\,dy\,dx}$

8 votes
Accepted

Differentiable injective function has non-zero derivative?

7 votes
Accepted

Calculate the probability of a "good" dice roll

6 votes

Boundaries of a definite Integral

6 votes

What/Where is the logical error in the second solution?

5 votes
Accepted

What minimizes mean absolute cubic error?

5 votes
Accepted

How many employees do I need to fill 33 positions? Real world problem

4 votes
Accepted

Evaluate limit of $\lim_{x \to 0} \frac{ (1 + x) ^{(1/5)} - (1 -x) ^ {(1/5)} } {x} $

4 votes
Accepted

Algebra of Limits/Limits involving Greatest integer Function

4 votes
Accepted

Why is $\sum_{k=2}^{\infty} \frac{k}{k^{2}-1}=\sum_{k=2}^{\infty}\left(\frac{1}{k-1}+\frac{1}{k+1}\right)$?

4 votes
Accepted

Probability that one person is selected and other is not selected in a group

4 votes

Area of isosceles triangle

4 votes
Accepted

Find $\lim_{n \to \infty} \frac{x_{n+1}}{x_n}$ if $x_n \to a$ when $n \to \infty$

4 votes

What is the flaw in this approach?

4 votes
Accepted

Functional inequality with integral function

4 votes
Accepted

How to find $\lim_{x\to-\infty} \frac{\sqrt{x^2+2x}}{-x}$?

3 votes
Accepted

Does the infinite limit probability of additive closure for pairs of elements from $(0, 1, 2 \cdots, n)$ not exist?

3 votes
Accepted

Probability of pair of gloves selection

3 votes
Accepted

Misapplication of the divergence theorem when calculating a surface integral?

3 votes
Accepted

Clarifications on differentiability and continuity

3 votes

My contour integrations seem to contradict the residue theorem.

3 votes
Accepted

How to prove that a point equidistant from each vertex of a regular polygon (the circumcentre) exists?

3 votes
Accepted

What is another more direct proof of this exercise?

3 votes
Accepted

when can't methods of undetermined coefficient be used in this case

3 votes

Calculate this limit without L'Hôpital's rule.

3 votes

Solving differential equation for density in a gas sphere

3 votes
Accepted

Converting polar unit vectors to Cartesian

3 votes
Accepted

Volume of solid of integration - trying to spot a silly error!

3 votes

Injective functions and composition

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