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Ant's user avatar
Ant
  • Member for 11 years, 3 months
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117 votes

'Obvious' theorems that are actually false

47 votes
Accepted

Why is uniqueness important for PDEs?

46 votes
Accepted

Can a number have infinitely many digits before the decimal point?

31 votes
Accepted

Why can the determinant be assumed to be 0?

28 votes

"What if" math joke: the derivative of $\ln(x)^e$

24 votes
Accepted

Can $n^2+4n$ be a perfect square?

21 votes

How to find Laurent series Expansion

20 votes
Accepted

If $A=AA^{\top}$, show that $A^2=A$

18 votes

Why doesn't L'Hôpital's rule work in this case?

18 votes

Formulae of the Year $2016$

15 votes

Why do we need rationalisation?

15 votes

Why do some integrals and derivatives have absolute values?

13 votes

Problem understanding the concept of a union

13 votes
Accepted

Repeated application of L'Hôpital on polynomials doesn't always work?

12 votes
Accepted

If $\sum_{i = 1}^n a_i b_i = \sum_{i = 1}^n a_i^2 = \sum_{i = 1}^n b_i^2$, then $a_i = b_i$ for all $i$.

12 votes
Accepted

How is substituting $-y$ for $y$ with $y \neq 0$ legal?

12 votes

Is there a real number which comes just after a particular real number?

11 votes
Accepted

Does $1^i$ and $1^{\frac{0}{0}}$ also give $1$ again?

11 votes
Accepted

Two divergent series such that their product is convergent

10 votes

Convert from base $10$ to base $5$

10 votes
Accepted

Does $\int_{1}^{\infty} g(x)\ dx$ imply $\lim\limits_{x\to \infty}g(x)=0$?

9 votes

What is the motivation behind the study of sequences?

9 votes

quick question on an example of the derivative as a linear map.

9 votes

To prove the sum is convergent

8 votes

Joint distribution of $U = X + Y$ and $V = X - Y$

8 votes
Accepted

Computing two variables limit

8 votes
Accepted

If $a>b$ then $a^a>b^a. $

8 votes
Accepted

What is the difference between identically distributed random variables ?

7 votes

Product of cdf and pdf of normal distribution.

7 votes

Finite sum calculation.

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