BrainDen.com - Brain Teasers

## Question

(Okay yes, this was inspired by an xkcd comic... )

Find the most accurate approximation (for the the units given) that has 5 characters or less (not counting negative sign or decimal point) for the following:

1) Gravitational constant: 6.673x10^-11 (m^3/kg/s)

3) Planck's constant: 6.026x10^-34 (m^2*kg/s)

4) Electron mass: 9.109x10^-31 (kg)

5) Boltzmann constant: 8.617x10^-5 (eV/K)

6) Permittivity of free space: 8.854x10^-12 (F/m)

7) Elementary charge: 1.602x10^-19 C

I.e. you could approximate a light-year as 99^8 (m).

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• 0

7^-12

5^34

56^-19

38^-19

22^-3

24^-8

22^-14

and here's my pseudo-code that produced it.

```
for i in range(2,100):

result = i**int(math.log(value,i))

if result/value > 1:

result = result/value-1

else:

result = 1-result/value

if result < aprox:

aprox = result

index = i

exponent = int(math.log(value,i))

print(index,exponent)

```

Edited by phil1882

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• 0

That's pretty good. In case my example confused anyone, you can also use things besides exponents (including operators), and you can use non-integers in exponents. Heck, go ahead and throw in pi (it can count as one character) and e if you want for fun .

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• 0

May be cheating but Avogadro's constant=R/K

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Pi47.83 Still trying to make it better/nicer.

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• 0

I came up with some others.

1) Pi-7.53e

5) 19.67-Pi

6) e-25.45

7) Pi-37.8

I went the Pi/e route.Planck's constant and Electron mass are still giving me troubles with using Pi or e.

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