Go back
4x4

4x4

Posers and Puzzles

Vote Up
Vote Down

arccos(4-4)-4-4=82

Vote Up
Vote Down

Originally posted by kbaumen
arccos(4-4)-4-4=82
An alternative:

4!/.4 + 4! - sqrt(4) = 82

There's something about these inverse trig formulations that isn't quite as satisfying.

Vote Up
Vote Down

Originally posted by mtthw
An alternative:

4!/.4 + 4! - sqrt(4) = 82

There's something about these inverse trig formulations that isn't quite as satisfying.
I dunno, I'm quite satisfied with 'em.

Vote Up
Vote Down

Originally posted by kbaumen
I dunno, I'm quite satisfied with 'em.
Oh, it's just a personal thing. I'm not saying they shouldn't be allowed.

1 edit
Vote Up
Vote Down

Originally posted by mtthw
Oh, it's just a personal thing. I'm not saying they shouldn't be allowed.
feel free not to use them ~ numbers up to 2178 are all possible without!

Edit

Apparently.

Vote Up
Vote Down

But even with them, it's kind a hard to get 83. I'm stuck on it for some 10 min.

Vote Up
Vote Down

(!4)^(sqrt(4)) + sqrt(4) = 83

Vote Up
Vote Down

Originally posted by Agerg
(!4)^(sqrt(4)) + sqrt(4) = 83
er.. what is (!4) ?

1 edit
Vote Up
Vote Down

Originally posted by Agerg
(!4)^(sqrt(4)) + sqrt(4) = 83
What is '!4'? is that meant to be '4!'? In that case your expression is flawed.

4!=24; sqrt(4)=2;
24^2+2 =/= 83

EDIT: And that's only three 4's.

4 edits
Vote Up
Vote Down

subfactorial...the total permutations of n elements excluding those that contain elements in their natural place

ie: !3 = 2

123, 132, 213, 321, all contain at least one element where it should be leaving only 132, and 312

!1 = 0, !2 = 1, !3 = 2, !4 = 9...

(though you got me on the 3 fours though! 😵 )

1 edit
Vote Up
Vote Down

Originally posted by Agerg
subfactorial...the total permutations of n elements excluding those that contain elements in their natural place

ie: !3 = 2

123, 132, 213, 321, all contain at least one element where it should be leaving only 132, and 312

(though you got me on the 3 fours though! 😵 )
Nice. I found an article in wikipedia about this. This can really be helpful. Only you need four, not three 4's in the expression.

Oops, didn't see your edit.

Vote Up
Vote Down

(!4)^(4 - sqrt(4)) + sqrt(4) = 83

Vote Up
Vote Down

44*sqrt(4) - 4 = 84

1 edit
Vote Up
Vote Down

Nevermind, it was wrong.

Vote Up
Vote Down

(!4)^(4 - sqrt(4)) + 4 = 85

Cookies help us deliver our Services. By using our Services or clicking I agree, you agree to our use of cookies. Learn More.