Recent content by Unitary

U
Poll: With which topics in Mathematics should the average high school senior be comfortable?

I have a PhD in Mathematics and am a Tenured Faculty (10yrs) at a 4-year public University. To me there's really two different answers here. If someone isn't going to college, I'd say a basic understanding of Algebra would be fine. For those going to College, I'd say a strong background in...
- Unitary
- Post #33
- Oct 29, 2016
- Forum: OT Discussion Club
U
CostCo USA dropping Amex for Citigroup VISA

Currently only Executive members get the Costco 2% back. This page seems to imply that everyone will now get 2% back at Costco. Wonder if that's the case.
- Unitary
- Post #383
- Mar 24, 2016
- Forum: OT Discussion Club
U
Stumped on math problem

I know I'm a bit late, but I thought I'd share another possible solution. Again using properties of mod, you first know that 7^2=49 is congruent to -1 (mod 10). In other words 7^2==-1 (mod 10) Take 16 powers of each side, (7^2)^16==(-1)^16 (mod 10), or (7^32)==1 (mod 10) Multiply each...
- Unitary
- Post #13
- May 20, 2014
- Forum: OT Discussion Club
U
Turn on, tune in, drop out. Falling objects question.

I don't think that they will land at the same time as the masses don't cancel out when you include wind resistance. True, when looking at the standard gravitational motion equation F=ma (without wind resistance) the masses do cancel out, it no longer does when you include the wind resistance...
- Unitary
- Post #39
- Oct 30, 2013
- Forum: OT Discussion Club
U
the event horizon of a black hole should be colorful

For a static black hole a photon would have a circular orbit at radius 3Gm (or 50% larger than the Schwarzshild radius) Unfortunately, no photons are trapped by this orbit as it is unstable. In other words, any perturbation from this orbit causes the photon to fall into the black hole or fly...
- Unitary
- Post #13
- Oct 25, 2013
- Forum: Ask a Technical Professional
U
[TOM'S] AMD inter-generational CPU shootout

This was certainly an interesting article, but I don't understand their constant Athlon II x4 bashing. Sure, it was the slowest processor of the bunch, but it is a budget cpu that came out four years ago. I'd instead offer a different conclusion, one that highlights that paired with a modern...
- Unitary
- Post #221
- Aug 22, 2013
- Forum: CPUs and Overclocking
U
f(a + b) = f(a) + f(b)

But that top limit doesn't exist.
- Unitary
- Post #29
- Jan 12, 2012
- Forum: OT Discussion Club
U
Non-linear springs, specifically "constant" force springs

If the spring gave the same force, no matter its displacement from equilibrium, it would be a linear spring as its force would be F_s=C. As for the physicality of a spring with these characteristics I think it would be hard to really call it a "spring".
- Unitary
- Post #2
- Oct 22, 2011
- Forum: Ask a Technical Professional
U
Anyone go to community college & transfer to a 4 year university?

I transferred from a CC to a Univ of California. The CC and UC had a transfer agreement where if I took certain classes and maintained a 3.0 gpa, I had automatic acceptance to the UC. The best part was that when I transferred all my lower division requirements were automatically satisfied and...
- Unitary
- Post #27
- May 20, 2011
- Forum: OT Discussion Club
U
What degree do you have?

General area is partial differential equations. More specifically I looked at the existence of shock wave solutions in relativistic gas dynamics.
- Unitary
- Post #62
- May 6, 2011
- Forum: OT Discussion Club
U
What degree do you have?

Ph.D. Mathematics, 10 years total, 5 years for B.S., 5 more for graduate work.
- Unitary
- Post #57
- May 6, 2011
- Forum: OT Discussion Club
U
for you math geniuses out there...

Please be more specific about your question. For example, where does "i=3" come into play in your sum?
- Unitary
- Post #10
- Sep 8, 2009
- Forum: OT Discussion Club
U
Linear Algebra

Linear Algebra is essentially the backbone for most of advanced mathematics. Unfortunately, most undergraduate classes focus too much on matrices for computation and vector space examples for this to be seen. It's too bad because there are many accessible and interesting examples of linear...
- Unitary
- Post #29
- Sep 3, 2009
- Forum: OT Discussion Club
U
Inverse function

Unfortunately, what you want to do is impossible. The function doesn't have an inverse on the domain x>0 because it is not one to one. Moreover, I think that even if you restrict the domain to where it does have an inverse (say x>1), it cannot be written in an elementary form (using roots logs...
- Unitary
- Post #2
- Jul 19, 2009
- Forum: OT Discussion Club
U
Math help - eigenvalues

Too bad that you believe this... couldn't be farther from the truth.
- Unitary
- Post #20
- Apr 12, 2009
- Forum: OT Discussion Club

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