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G Cab's user avatar
G Cab
  • Member for 8 years, 3 months
  • Last seen this week
  • Rieti, Italy
46 votes

Finding three unknowns from three equations. Solvable? If so, how?

33 votes

Consecutively Adding Sines

33 votes

Equation of a "tilted" sine

24 votes

Mathematical ideas that took long to define rigorously

22 votes

What is the tangent at a sharp point on a curve?

18 votes

A ping-pong ball lying inside a wine glass

13 votes

The staircase paradox, or why $\pi\ne4$

13 votes

Prove $\int_{0}^{\pi/2} \int_{0}^{\pi/2} \frac{\theta\cot\theta-\varphi\cot\varphi}{\cos\theta-\cos\varphi} \text{d}\varphi\text{d}\theta = \pi\ln2$

12 votes

If I roll three dice at the same time, how many ways the sides can sum up to $13$?

11 votes
Accepted

Algebraic expansion of $(1+x)^{1/x}$ is?

11 votes

Why won't a series converge if the limit of the sequence is 0?

10 votes

The formulas of prostapheresis: memorization technique

9 votes

Is there an "inverted" dot product?

8 votes
Accepted

The asymptotics of the products over primes $\prod\limits_{2<p\le n}\left(1 - \frac1{p-1}\right)$

8 votes

To prove: $n!=\sum\limits_{r=0}^n (-1)^r \binom{n}{r} (n-r)^n$

8 votes
Accepted

partial derivative of cosine similarity

8 votes

What is the probability that four players who each receive ten cards together receive less than four aces?

8 votes

The sum of series with natural logarithm: $\sum_{n=1}^\infty \ln\left(\frac{n(n+2)}{(n+1)^2}\right)$

8 votes
Accepted

Proving that $f$ verifies $f(1-x)=-f(x)$

8 votes
Accepted

Why does this method for solving cubics seem to fail?

8 votes

properties that real numbers hold but complex numbers does not

7 votes

PDF of area of triangle with normally-distributed coordinates in any dimensions

7 votes

Splitting $r^k (r+n)!$ as a sum of factorials

7 votes

Paradox about the volume of a cylinder

7 votes
Accepted

Why is vertical distance the standard in least squares?

7 votes

Confusion about order of rotations for Euler Angles

7 votes

Value of the binomial series $\sum_{i=0}^k \frac{{2i \choose i}}{4^i}$

6 votes

For real numbers $x,y$ satisfy the condition $x^2+5y^2-4xy+2x-8y+1=0$. Find the Maximum and Minimum Value of the expression $A=3x-2y$.

6 votes

Determine the rotation necessary to transform one point on a sphere to another.

6 votes

Orthogonal Projection Area of a 3-d Cube

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