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Aug
23
comment how do you solve $(x^2-5x+5)^{x^2-36} =1$
What about $a=\mathrm e$ and $b=2\pi\mathrm i$?
Aug
23
comment Intuition about an orthogonal projection operator for matrices
Since $\mathcal P_T$ maps between two different spaces, it cannot be a projector, since the defining equation $P^2=P$ is not even defined for $P=\mathcal P_T$.
Aug
23
comment Intuition about an orthogonal projection operator for matrices
Ah, I see. But "projectors onto $U$ and $V$" doesn't make sense. Rather, they are the projectors onto the image and the orthogonal space of the kernel.
Aug
23
comment Intuition about an orthogonal projection operator for matrices
Since $U$ and $V$ in the real SVD are orthogonal, $UU^T$ and $VV^T$ are both the identity. While technically the identity is an orthogonal projector, I'm pretty sure it's not what you had in mind.
Aug
23
revised The value of limit $y^3/(x^3 – y^2 - 1)$ as$ (x,y) \rightarrow(1,0) $along the line$ y = x-1$?
fixed LaTeX in title
Aug
22
comment Find the limit (as x approaches 1) of : $|x^2+x-2|/(x^2-1)$
I notice that the output of the limit calculators is the average of left and right limit. Coincidence?
Aug
22
comment How to simplify $x^{1/2}$
I'm not sure I'd consider $1/x^3$ to be simpler than $x^{-3}$.
Aug
22
comment How do 24 significant bits give from 6 to 9 significant decimal digits?
Why are you assuming rounding down instead of rounding to nearest?
Aug
22
comment How do 24 significant bits give from 6 to 9 significant decimal digits?
@Kareem: How many different values can you represent with 23 bits?
Aug
19
comment Is it true that Ackermann's function cannot be implemented without recursion?
How would you implement the up-arrow operation without recursion?
Aug
19
comment Determining if two numbers are relatively prime.
@AnthonyHernandez: I showed that for any prime other than $2$, if is is a factor of $s$, it isn't a factor of $\phi_2(s)$. Thus it also isn't a factor of the gcd. Thus the only prime factor the gcd can have is $2$. Numbers with that property are known as "powers of $2$".
Aug
18
comment Determining if two numbers are relatively prime.
@joriki: Right; fixed it. Thank you.
Aug
18
revised Determining if two numbers are relatively prime.
fixed error
Aug
18
answered Determining if two numbers are relatively prime.
Aug
18
answered Extension of metric definition to two sets
Aug
15
comment Power set empty set confusion
"The elements of sets may very well be sets themselves" — indeed, at least in standard set theory, they may only be sets.
Aug
15
comment True or false. If A ∪ B = ∅ , then A = ∅ and B = ∅ .
Strictly speaking, since an universal set $U$ is assumed of which all sets are subsets, 2 is only false if $U$ has at least two elements.
Aug
15
comment True or false. If A ∪ B = ∅ , then A = ∅ and B = ∅ .
I guess in 4, it should have been $A\subset B$, not $A\in B$.
Aug
15
comment Generalized modulo arithmetic
@egreg: I've corrected that mistake.
Aug
15
revised Generalized modulo arithmetic
fixed errors