Category Archives: Math

Math is Hard

Posted on by
Reply

Here’s your annual reminder that 22/7 is a more accurate approximation of pi than 3.14.

Which reminds me of pie. Here’s my son’s recipe for apple pie.

Make the filing of equal amounts of Stayman Winesap and Pink Lady apples tossed together with Grade B maple syrup (that’s the dark kind with extra solids). Put the filing in a pie shell and add the lattice top made of butcher cut bacon. The bacon will shrink while cooking, so the ends will initially droop over the edge of the pie shell. Bake in a 350 °F oven until the shell and bacon are done. Put a drip pan under the pie to catch drips from the bacon.

Meanwhile, Back in the Real World …

Posted on by
Reply

I wound up spending most of the holiday weekend lashed to a computer but not on the Interwebz.

While taking Real World performance data on a bit of hardware last week, my colleagues and I discovered some odd behavior that was not completely unexpected but had not been predicted by the original modeling of the circuit. I’ve spent a large part of the past few days refining that model. I’ve improved it to the point where it will do the same kind of tricks as the Real World circuit, but not yet in exactly the same way.

It turns out that a couple of the components are more temperature sensitive than assumed in the original model. The warming isn’t global. It’s just a local phenomenon, and the unexpected performance has turned out to be a feature rather than a bug.

Math is Hard

Posted on by
2

Karine Jean-Pierre really said this—

Look, when you look at the data, the inflation data, we’re seeing more progress, bringing global inflation down in the U.S. economy, as I just stated moments ago. Overall, uh, prices have been essentially flat in our country these last two months. That is welcome news for American families.

OTOH, if you believe Nineteen Eighty-Four is an instruction manual rather than a warning, then arithmetic is subject to revision as required. Two plus two can be five or three or four or whatever The Party needs it to be.

My 401k and rollover IRA were unavailable for comment.

BTW, I almost posted this with an I’m Not Making This Up, You Know headline.

I’m Not Making This Up, You Know

Posted on by
Reply

Really?

My rifle chambered in .17 Remington fires a 25 grain bullet with a muzzle velocity just over 4,000 ft/s. Now, my AR-15 is chambered for 7.62x39mm (It’s a long story), but I doubt that it launches one of the 123 grain bullets in the Hornady ammo I use for deer hunting at 20,000 ft/s. That would result in a muzzle energy over 100,000 ft•lb. which about 8 X the muzzle energy of a round fired from a .50 cal. M2 machine gun. My AR doesn’t seem to kick that hard.

UPDATE—FWIW, the typical muzzle velocity of a bullet fired from an AR-15 chambered for common 5.56x45mm ammunition is about 3,150 ft/s. The only combination of firearms and ammunition that I can find in my gun safe and ammo locker that could produce a muzzle velocity as low as 625 ft/s (1/5 of 3,150) would be a short-barreled revolver loaded with .22 Shorts or a muzzle-loading rifle with a dangerously low powder charge.

Team Kimberlin Post of the Day

Posted on by
Reply

Team Kimberlin never lets facts get in the way of their narratives—or math either, as this Math is Hard post from six years ago today demonstrates.

* * * * *

PP201606061457ZCentral TimeCentral Daylight Time (CDT) is 5 hours behind Coordinated Universal Time (UTC).

9 – 5 = 4

10 – 5 = 5

 

 

 

 

 

* * * * *

Yes, and two and two are still four.

Coal Fired Teslas

Posted on by
1

The electricity flowing from a charging station doesn’t magically appear. It must be generated and transmitted to the charger.

Let’s do a bit of analysis.

Looking around the interwebz, I found that the typical Tesla uses 34 kWh of energy to go 100 miles. I’m more used to dealing with energy calculations in joules. 34 kWh = 122 MJ. That’s megajoules.

The typical charging station has an efficiency of about 90 %. In order to deliver 122 MJ to the Tesla’s battery, it will draw about 136 MJ from the power line. The typical efficiency of the power grid from generating station to end user is about 89 %. Some power station needs to generate 153 MJ to get 122 MJ into the Tesla’s battery.

Let’s assume it’s a modern coal fired plant. The efficiency of the process of burning coal to heat water to make steam to turn a turbine to spin an electrical generator is typically around 32 %. That means we need 472 MJ of energy from the coal.

Burning a ton of coal delivers about 22 GJ (gigaojoules) of energy, so we’d need to burn about 43.4 pounds of coal to charge a Tesla to drive 100 miles. That gives a fuel economy rating of 2.3 miles per pound of coal, and that’s roughly equivalent to 15 mpg for a gasoline vehicle.

YMMV

Quote of the Day

Posted on by
Reply

It is known that there are an infinite number of worlds, simply because there is an infinite amount of space for them to be in. However, not every one of them is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds, so the average population of all the planets in the Universe can be said to be zero. From this it follows that the population of the whole Universe is also zero, and that any people you may meet from time to time are merely the products of a deranged imagination.

—Douglas Adams

Taxing Unrealized Capital Gains

Posted on by
1

Lots of folks have seen the value of certain capital assets rise significantly over the past couple of years. One of the reasons my 401k has done so well is that several of the mutual funds in that portfolio have positions in companies such as Tesla, SpaceX, and Apple. I haven’t become a billionaire, but I’ve been along for the ride.

So now, the some of the more economically-challenged on the Left are proposing a “wealth tax” as a way of funding the Build Back Better scam. I saw a tweet this morning suggesting that because Elon Musk had seen his stock portfolio rise $36 billion recently, he should be hit with an $8 billion dollar tax bill. Musk seems to be a very savvy enough businessman. I doubt he keeps that kind of cash on hand. I’ll bet he’d have to sell a substantial part of his holdings in order pay up.

That leads to these questions—

If he dumped a large chunk his stock in companies like Tesla and SpaceX, wouldn’t that cause a drop in the prices of those stocks? Supply would suddenly exceed demand in the stock market. What could happen to my 401k? If it suffers an unrealized capital loss, should I get a tax rebate?

If he had to sell so much stock that he lost control of the companies, would the new owners keep him? If not, would they be as well run? Would the value of the holdings in my 401k be further depressed. How many jobs might be lost if the companies’ are as well run?

If destroying the businesses run by one of the richest men on the planet would only provide $8 billion (less than 0.25 % of the $3.5 trillion advertised price of Build Back Better), are the enough other fortunes that could be raped to fund the scam? And with so many business trashed and jobs lost, what would happen to income tax revenue?

Inquiring minds want to know.

Math is Hard—Logic is Harder—and Facts are Stubborn

Posted on by
Reply

Today, Joe Xiden said that 350,000,000 Americans have now been vaccinated against the Wuhan virus. Here’s a snapshot of the U.S. Census Bureau’s online population clock taken at 12:18:39 ET this afternoon—His Fraudulency is also encouraging those Americans who haven’t yet been vaccinated to get their shots.

I was going to write a longer post about vaccination records possibly being processed by the people who counted votes last November, but I’ve got real work to do.

Is it 2025 yet?

The Physics of Filtering

Posted on by
2

When I was small child, our family lived in house without air-conditioning. We had screens on all the windows and an attic fan to cool the house. The gaps in the screens were small enough to prevent flies and mosquitos from entering the house. It would have been foolish to replace the screens with chain link fencing and expect that the bugs would still be kept out. A housefly has a wing span around 1/2 lnch, and the wires in chain link fencing are a couple of inches apart. The gap is about four times the size of a fly. A fly can easily pass through.

The gap between fibers in a typical cloth face mask is on the order of 2 to 3 micrometers. The coronavirus is on the oder of 0.3 micrometers.

The mathematics of the filtering is left to the Gentle Reader as an exercise.

Math and Science Are Hard

Posted on by
1

I was puzzled by the CDC’s recent claim that the Wuhan Virus Pandemic had cased a one year drop in life expectance in the U. S. It turns out that their claim is so screwed up it isn’t even wrong. If life expectancy has dropped because of Covid, the decline is probably less than a week, an amount so small that it’s inside the roundoff error of the statistics. Eugene Volokh has a post up with details from a report by Dr. Peter Bach.

Analysts estimate that, on average, a death from Covid-19 robs its victim of around 12 years of life. Approximately 400,000 Americans died Covid-19 in 2020, meaning about 4.8 million years of life collectively vanished. Spread that ghastly number across the U.S. population of 330 million and it comes out to 0.014 years of life lost per person. That’s 5.3 days. There were other excess deaths in 2020, so maybe the answer is seven days lost per person.

No matter how you look at it, the result is a far cry from what the CDC announced.

It’s not that the agency made a math mistake. I checked the calculations myself, and even went over them with one of the CDC analysts. The error was more problematic in my view: The CDC relied on an assumption it had to know was wrong….

Apparently, 2 + 2 equals whatever the public health establishment needs it to be.

Solving the Problem of Woke Math

Posted on by
2

There’s an excellent review of woke math over at Legal Insurrection. Go read it; it does a better job of summarizing the danger to our society.

However, I have a suggestion about how to shutdown woke math education in the schools. Simply calculate the pay of any teacher or education bureaucrat using or promoting woke math on the basis of 2 + 2 = 3.

Quote of the Day

Posted on by
1

Thermodynamics is a funny subject. The first time you go through it, you don’t understand it at all. The second time you go through it, you think you understand it, except for one or two small points. The third time you go through it, you know you don’t understand it, but by that time you are so used to it, it doesn’t bother you any more.

—Arnold Sommerfeld

A $15 Dollar an Hour Minimum Wage is Racist

Posted on by
Reply

All the arguments that have been presented for increasing the minimum wage to 15 bucks an hour rely on claims that a lesser wage does not provided enough money to a worker. Such claims are based in the use of arithmetic to compute the worker’s financial status and implicitly endorse the proposition that there is such a thing as a “right answer.” However, it now received educational theory that the very idea of a “right answer” is a racist concept. Thus, in order to advance minorities and suppress white supremacy, it is vital that we not only defeat the Fight for Fifteen but also must also repeal the existing minimum wage laws that have been used as tools of oppression for decades.

Don’t Know Much About Algebra

Posted on by
5

For those of you who don’t know the Sam Cooke song Wonderful World (the first line of that song is “Don’t know much about history …”), this is a line from the second stanza. I think it makes a good headline for a post about teachers who don’t understand math.

Fox reports that the Oregon Department of Educations is seeking to undo white supremacy in mathematics education. The minicourse being offered to teachers

includes a list of ways “white supremacy culture” allegedly “infiltrates math classrooms.” Those include “the focus is on getting the ‘right’ answer,” students being “required to ‘show their work,'” and other alleged manifestations.

“The concept of mathematics being purely objective is unequivocally false, and teaching it is even much less so,” the document for the “Equitable Math” toolkit reads. “Upholding the idea that there are always right and wrong answers perpetuate objectivity as well as fear of open conflict.”

I wonder how many of the education bureaucrats who are promoting the course would object to the calculations on their paychecks being done on the basis of 2 + 2 = 3.

Unjust Justice

Posted on by
2

Rev. William Barber has a post over at In These Times about The Fight for a $15 Minimum Wage Is a Fight for Racial Justice. He quotes a loose translation of the beginning of the 10th chapter of Isaiah in support of his argument—

Woe unto those who legislate evil and rob the poor of their rights, who make women and children their prey.

I agree with Rev. Barber that those of us who are better off have an obligation to treat the poor justly and to compassionately care for widows and the fatherless. However, I believe the minimum wage increase he supports will hurt rather than help the poor. Indeed, passing such a law will be legislating an evil.

The general effect of increasing the minimum wage is to price workers with marginal skills out of the labor market. Businesses don’t have bottomless funds from which they pay wages. They can only extract so much revenue from their customers, and that money must be divided among paying for inventory, rent, wages, and other expenses. A minimum wage bill doesn’t make expenses like rent disappear, so a business only has so much it can divide among its workers for payroll. When the law artificially increases each worker’s pay, simple arithmetic shows that fewer workers can be paid before the money is gone. Business that survive will keep their best employees and fire marginal workers. Business that grow will hire fewer workers.

Not every worker who loses his job because of a minimum wage increase will remain unemployed. Some will find work off-the-books in the informal economy, but increasing the minimum wage invariably increase unemployment among our poorest citizens.

We Americans generally believe that everyone has a right to work to support himself and family. Is it just to pass a law artificially pricing poor workers out of the labor market? I don’t think so.