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1h
comment What does it mean “choose one randomly”?
It depends if the use of the word "randomly" implies a mathematical sense of randomness, or if it is used as a synonym for "arbitrary". In the latter case, one doesn't need a distribution. The point is that the choice of element is unimportant.
1h
comment Updating a real time plot in Matlab
There are literally dozens of ways to do this. Can you describe more about the tools you're using?
2d
comment Gradient Method of solving $\mathbf{Ax}=\mathbf{y}$
Note that $y$ is a vector, and $Ax$ is a vector, so $y-Ax$ is a vector, and the vector dot product can equivalently be written as $v\cdot v = v^Tv$.
Apr
11
comment Totally lost and frustrated
Math.SE has been a good community, and the chat rooms offer opportunity for real-time discussion, too!
Apr
9
comment Algorithm - if known $x$ and $y$ value
A polynomial interpolant is like the least clever thing out there ;)
Apr
9
answered What does $e^b$ means?
Apr
9
answered Algorithm - if known $x$ and $y$ value
Apr
1
comment Why is a zero vector space a vector space
They're variables. They're assumed to take any value in their domain, of course they can be the same value. Or different values. Or any pair of values in the domain!
Mar
31
revised $X$ is an Alexandroff space iff each point in $X$ has a minimal open neighborhood.
fixed the weird ff in the title
Mar
31
comment Prove condition number of a invertible matrix is atleast one
Embed the entire superscript in braces: A^{-1} results in $A^{-1}$.
Mar
31
comment What does “versus” mean in the context of a graph?
I would agree with the rule "[dependent] versus [independent]." The word "versus" can mean "compared with," and it more frequently makes sense to compare a dependent value with its associated independent value, because well, the independent variable doesn't really "care" about the existence of the dependent variable, but the converse relationship is by definition.
Mar
30
answered How do you rearrange equations with dot products in them?
Mar
25
answered Finding $-8$ in $\Bbb Z \pmod 5$
Mar
25
comment Determining constant in a CDF
For what it's worth, although this may seem like needless generalization, it actually makes sense when you begin to look at probability theory in a measure-theoretic sense. Having these general definitions allows us to write theorems without having to consider a bevy of special cases.
Mar
25
comment Determining constant in a CDF
Yes, so effectively the condition $F \to 0$ as $x \to -\infty$ can be replaced with $F \to 0$ as $x \to 0$ and $F = 0$ for $x \le 0$. These latter conditions obviously satisfy the former.
Mar
25
comment When does the Newton Raphson method fail?
In fact, some several trips around the sun ago, I recall this exact example being on my numerical analysis final exam.
Mar
25
comment Determining constant in a CDF
I don't know. I think it induced you to ask a very good, natural question and to think carefully about the problem and the definitions.
Mar
25
answered When does the Newton Raphson method fail?
Mar
25
comment Determining constant in a CDF
@JasonZimba It's just forcing you to think a little bit. There are two constraints on $\theta$: $\theta > 0$ which is enumerated explicitly, and $\theta \le 3$, which is implicit given that we're given $F$ as a valid CDF.
Mar
25
comment MRAC Adaptive Control Gains
I still have no idea if by "I'd like to plot" you mean "how do I plot a signal", "how do I extract a signal", or "how do I obtain a mathematical relationship for these gains." As in, you reference some modeling in MATLAB, so do you have the MRAC working? Are you computing $K_x$ and $K_r$? Are you looking for a technique on how to compute it?