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bio website mathsci.appstate.edu/~cookwj
location Boone, NC
age 34
visits member for 3 years, 3 months
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Assist Prof. at Appalachian State University (in Western North Carolina)


1d
answered If $|G| = 2^n$, then there is a subset $S$ of cardinality $n$ such that $S$ generates $G$.
Dec
20
answered Tangent Vector at the point $(1,2,11)$ whose projection onto the $xy$-plane is parallel to vector $1/\sqrt{10}i+3/\sqrt{10}j$.
Dec
20
awarded  Constituent
Dec
19
comment Does a subring of $\mathbb{Z}$ need to be closed under multiplication?
Ok then. "subrngs". Not everybody assumes their rings have multiplicative identities. Many universities use Joe Gallian's text. It's an example of a text which allows for rings without (multiplicative) identity.
Dec
18
comment Does a subring of $\mathbb{Z}$ need to be closed under multiplication?
@DietrichBurde No this isn't a duplicate (of that question anyway). The subring test for this particular ring can be weakened.
Dec
18
revised Does a subring of $\mathbb{Z}$ need to be closed under multiplication?
added 31 characters in body; edited title
Dec
18
answered Does a subring of $\mathbb{Z}$ need to be closed under multiplication?
Dec
18
comment Tangent Vector at the point $(1,2,11)$ whose projection onto the $xy$-plane is parallel to vector $1/\sqrt{10}i+3/\sqrt{10}j$.
Isn't it just $f(1,2)=1^32^2+3(1)+2(2)=11$?
Dec
18
revised Tangent Vector at the point $(1,2,11)$ whose projection onto the $xy$-plane is parallel to vector $1/\sqrt{10}i+3/\sqrt{10}j$.
added 81 characters in body; edited title
Dec
18
awarded  calculus
Dec
17
comment Every point in the codomain is a regular point
No. Choose y=0 then x=1/sqrt(2). You get a=1/2. Then choose z to make b=1/2 and you get another solution.
Dec
17
awarded  Good Answer
Dec
17
awarded  Enlightened
Dec
17
comment Looking for a primitive …
It's just too general of a system to have a nice, clean closed form solution. Oh well.
Dec
16
comment Units of $\overline{\mathbb{Z}}$
What is $\bar{\mathbb{Z}}$?
Dec
16
answered Can someone help me understand the proof that every cauchy sequence is bounded?
Dec
16
comment Every point in the codomain is a regular point
You neglected to take into account where the partials of $a$ and $b$ can be zero. For example: $x=y=z=0$ yields a singular point.
Dec
16
answered Looking for a primitive …
Dec
16
comment Quasi Cauchy sequences in general topology?
You might want to rewrite your question using more words and less symbols. You may also want to define several of the symbols used as well. For example: $\Delta X^2 = \{ (x,x) \;|\; x \in X\}$.
Dec
16
answered How to find a recursive formula for some sequence