# April 6. Coronavirus and the Roots of 2

We’ve been calculating the Percent Increase of cases in leading and nearby domains.  But we have only occasionally referred them to the other way people look at these as how many days does it take to double at given percent increases.  On the logarithmic plots of cases, these are the radiating straight lines bounding the evolution graphs.  So we have constructed the roots of two to the accuracy which I have been computing the tables.

The square root of two is well known as 1.414.  That means that if you compound at 41.4% for two days, you double your initial principal.  Here is a table up to a week or seven days of compounding.

 Days to Double. The root of 2. The daily percent increase 1 2 100% 2 1.414 41.4% 3 1.260 26.0% 4 1.189 18.9% 5 1.149 14.9% 6 1.126 12.6% 7 1.104 10.4% 8 1.0905 9.05% 9 1.08o1 8.01% 10 1.0718 7.18%

I’m really worried at any domain with 26% or higher percent increase.  You can see why 19% to 26% is the next category to worry about.  For only a one week doubling, you have to get down to 10%.

US deaths are 10,986.  This is dominated by New York at 4,758, including 3.485 from New York City.  New Jersey is next at 1,003, and then Michigan at 727.  California had 388 deaths total.

Remember when the world death rate from the Coronavirus was 3.4%, and Trump argued that it should be much less than 1%?  The US Coronavirus death rate is 3.0%, and the California death rate from it is 2.4%.

 Domain Cases Percent Increase US 368,241 18.0% NY 131,815 15.5% NJ 41,090 20.4% MI 17,221 21.1% CA 16,347 17.6% LA 14,867 19.0% MA 13,837 17.9% FL 13,629 18.1% PA 13,206 25.7% IL 12.262 18.9% WA 8,384 7,632 TX 8,154 18.7% GA 7,558 18.4% CT 6,906 30.9% CO 5,183 13.5% IN 4,956 25.4% OH 4,953 19.1% MD 4,045 27.5% TN 3,802 14.4% NC 3,054 21.8% VA 2,878 19.6% MO 2,736 16.7% AZ 2,732 22.2% WI 2,511 18.0% SC 2,232 8.93% AL 2,006 8.96% NV 1,970 7.30% Canada 16,667 19.0% Mexico 2,439 29.0% Brazil 12,232 18.1% Los Angeles County 6,360 20.5% Orange County 882 12.2%

The really fast growths start with Connecticut at 30.9%, Mexico at 29.0%, Maryland at 27.5%, Pennsylvania at 25.7%, and Indiana at 25.4%.  A lot of states and Los Angeles were in the 20% region, and the entire US is at 18.0%, which doubles in about 4 days, as does Canada.

## About Dennis SILVERMAN

I am a retired Professor of Physics and Astronomy at U C Irvine. For a decade I have been active in learning about energy and the environment, and in lecturing and attending classes at the Osher Lifelong Learning Institute (OLLI) at UC Irvine.
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