Help! - maths

Quote:

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Originally Posted by ian

how about

find the missing number (x)
SQRT (169)
SQRT (25)
SQRT (x)

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I go with 4.

Although 1,5,13 is a recognized sequence, being given only 2 values of a sequence I would argue there is actually no correct arithmetic answer as there is nothing other than elegance to solve for. Unlike the original challenge.

3 fits in that sequence also therefore x could equal 9

Now, how does one 'add' -21?

The minus sign means that you subtract 21 from the other total.

So in the original question 28 + 29 = 57 57 - 21 = 36 The square root of 36 is 6 (6 x 6 = 36)

Quote:

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Originally Posted by Fuzzie

If only Clinton's original challenge had to do with some sort of prime number calculation.

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Quote:

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Originally Posted by ian

how about

find the missing number (x)
SQRT (169)
SQRT (25)
SQRT (x)

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Quote:

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Originally Posted by Fuzzie

Although 1,5,13 is a recognized sequence, being given only 2 values of a sequence I would argue there is actually no correct arithmetic answer as there is nothing other than elegance to solve for. Unlike the original challenge.

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Perhaps too elegant a challenge.

I was picking up Fuzzie's request for a challenge involving prime numbers.

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

Quote:

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Originally Posted by Big Shed

It is also wildly off-topic.

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Quote:

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Originally Posted by AlexS

Yeah, but...:D

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Oh, pictures please! :U

Quote:

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Originally Posted by ian

how about

find the missing number (x)
SQRT (169)
SQRT (25)
SQRT (x)

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So X would be 9.

A better scenario would be;
SQRT (169)
SQRT (121)
SQRT (49)
SQRT (25)
SQRT (x) Where x=9
Or the SQRT results 13, 11, 7, 5, and 3

OK, the horse is dead.

Quote:

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Originally Posted by AlexS

Better yet, x=-1

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I'm fairly certain that i is not a prime number

Quote:

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Originally Posted by rrich

So X would be 9.

A better scenario would be;
SQRT (169)
SQRT (121)
SQRT (49)
SQRT (25)
SQRT (x) Where x=9
Or the SQRT results 13, 11, 7, 5, and 3

OK, the horse is dead.

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Now that is an elegant prime number problem

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.

Quote:

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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.

Quote:

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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

Quote:

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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.