Stops of light explanation

[clanthar]

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610

The two first terms of the Fibonacci sequence are missing. 0,1,1,2,3,5,8......

But would they be missing for L. Fibonacci? When Fibonacci lived in Italy (1200), the common numbering systems was Roman. And the Roman Numeral for Zero is_________ ???

Fibonacci gets credit for encouraging the switch to Hindu/Arabic numerals that did include zero and Fibonacci was certainly aware of the concept. but when he enumerated that famous sequence he was participating in a math competition. Emperor Frederick II sponsored the competition with this problem: Beginning with a single pair of rabbits, if every month each productive pair bears a new pair, which becomes productive when they are 1 month old, how many rabbits will there be after n months? The problem didn't start with zero rabbits and so for the sake of historical accuracy I started the sequence with 1.

Joe

 

[480sparky67 66]

Are we supposed to guess?

3.14152653897923842643832750288. (the length of a half circle expressed in units of radius of that circle)

1.73. (square root of 3 rounded to two decimal places)

299,792,458 (approximate speed of light in km/hr)

I guess that goes back to my school days. A numerical answer was considered incorrect unless the UOM is attached to it. 2, 2.8, 4, 5.6... what? Dollars? Kilograms? Gallons? Amps? Just rattling off a series of numbers is pretty much meaningless, and that's what my 3 'random' numbers represent.

 

[KmH]

Square root of 2: 1.41421 35623 73095 04880 16887 24209 69807 85696 71875 37694 80731 76679 73799....

1 times 1.41421 = 1.14121 rounded = f/1.4

1.4 time 1.41421 = 1.979894 rounfded = f/2

2 times 1.41421 = 2.82842 rounded = f/2.8

2.8 time 1.41421 = 3.959788 rounded = F/4

Yada, yada, yada.

But for a stop of shutter speed and ISO just use x or / by 2.

1/500 is twice as fast a shutter speed as 1/250, and ISO 3200 is half as sensitive to light as ISO 6400.