Help! - maths

Perhaps for that challenge the given sequence should just be x,25,49,121,169. Providing the sqrt() clue being redundant?

BTW, Ian your challenge beat me. The sqrt() function actually made it solving the problem given 3 elements not 2! My bad.

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Originally Posted by ian

5 and 13 are both prime, the third number, while not a prime involves solving a right triangle.

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12.

5, 12, 13 where 5 and 12 are the sides of a triangle adjoining the right angle and 13 is the hypotenuse.

In a right angled triangle, the sum of the squares of the 2 sides equals the square of the hypotenuse. (5x5) + (12x12) = (13x13)

It is along time since I learned that t high school but has stuck as has 3,4,5 for the same purpose.

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Originally Posted by Ari2

I go with 4.

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4 fits because it follows the Fibonacci sequence. 0,1,1,2,3,5,8,13,21....

13 sqrd = 169
5 sqrd = 25
2 sqrd = 4

So it works if you skip the 3 and 8 in the sequence.

:)

I have been following this thread with interest. I admit I'm lost with all the prime and SQRT lingo, but I'll make my contribution.
When I was building and servicing CNC machines I had to learn Hex.

First 10 prime numbers in Hex.
2
3
5
7
B
D
11
13
17
1D

And in Octal
2
3
5
7
13
15
21
23
27
35

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Originally Posted by Chesand

12.

5, 12, 13 where 5 and 12 are the sides of a triangle adjoining the right angle and 13 is the hypotenuse.

In a right angled triangle, the sum of the squares of the 2 sides equals the square of the hypotenuse. (5x5) + (12x12) = (13x13)

It is along time since I learned that t high school but has stuck as has 3,4,5 for the same purpose.

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That's the answer I was looking for.

When I was trying to explain hexadecimal to my wife (a futile task, of course) I resorted to using the terms sixteenty and thirtytwoty.:D

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Originally Posted by Fuzzie

Never, I've always played with real computers. :)
My first introduction to reverse polish was in 1971 learning Fortran from McCraken's manual.
I think I wrote my own first usable RP calculator program in about 1981 on a Prime computer.

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I don't remember what my first calculator was, but I know it could spell hELL0 and ShELL :D

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Originally Posted by Grumpy John

I don't remember what my first calculator was, but I know it could spell hELL0 and ShELL :D

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I remember setting up equations that would result in 80085

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Originally Posted by BobL

I remember setting up equations that would result in 80085

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It took a second or two, then the penny dropped:clap3:.

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Originally Posted by BobL

I remember setting up equations that would result in 80085

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A sick bunch are we.

Hi,
I remember one were the answer described the young lady who's measurements were entered as 80087355.
:wink:
Regards