"Exponential Growth"

 

I recently heard someone say in a television interview that incidence of the corona virus was increasing, but not increasing exponentially. That is an absurd claim.

"exponential" is being misused to mean 'fast' by people who do not know what it means, but use it because they hear clever people using it and think that if they use it they too will appear clever.

A quantity q changes exponentially  when:

q_t =q₀*k^t where q₀ is the initial value of q,

q_t is the value of after t time units, and k is a constant. Positive k corresponds to exponential increase, and negative k to exponential decrease.

Increases of the incidence of the corona virus will always be approximately exponential until near the very end of the epidemic when most people will be immune. Until then the rate at which people catch the virus will be roughly proportional to the number already infectious. That implies exponential growth or decay

What Could we Buy for 4p ?

 

I was intrigued by the price in the following extract from the latest newsletter from the District Council.

"Our large waste items for collection service allows for up to three large household items or 12 sacks of waste to be collected for a charge of £35.04."

I wonder how someone arrived at that figure ?

What Became of Burton's ?

 

In the 1960 s and 70 s I used to buy suits from Burton's. They measured me and after a while I would be summoned for a fitting. The clothes fitted, lasted for a good while, and were not particularly expensive, but then Burton's shops seemed to disappear. I don't recall seeing one in the last thirty years. I thought the company had faded away until I saw the news of the collapse of the Arcadia group, which apparently owned Burton's. Where was the company hiding in the years since I last patronised it?

The Garden in December

 Flowers still abound in the garden. I don't remember ever seeing so many in December. Apart from the yellow Winter Jasmine and the hardy cyclamen that usually flower around this time, there are the white Summer jasmine, blue campanulas, begonias, feverfew, fuchsias, Mexican daisies, rudbekia, a couple of late flowers on the hydrangea, some zonal pelargoniums, often miscalled 'geraniums' and some flowers on old strawberry plants.

I usually try to avoid repetition in this blog, and worry that this post is very similar to one I posted last month, but think the difference between November flowers and December flowers is big enough to justify saying much the same thing twice.