Find the sum of all positive integers a

In summary, the formula for finding the sum of all positive integers a is (n(n+1))/2, and can also be found using the formula Sn = (n(a1 + an))/2. This sum can be calculated using a calculator, and there is a shortcut or trick using the formula (n(n+1))/2. However, it is not possible to find the sum if the series is infinite, as it would approach infinity and cannot be accurately calculated.
  • #1
anemone
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Find the sum of all positive integers $a$ such that $\sqrt{\sqrt{(a+500)^2-250000}-a}$ is an integer.
 
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  • #2
anemone said:
Find the sum of all positive integers $a$ such that $\sqrt{\sqrt{(a+500)^2-250000}-a}$ is an integer.

let m=$\sqrt{\sqrt{(a+500)^2-250000}-a}----(*)$

n=$\sqrt{(a+500)^2-250000}< a+500$

$m<\sqrt{500}\,\, or\,\, m\leq 22$---(1)

$n=\sqrt {a(a+1000)}=\sqrt{a(a+2^35^3)}$

min(a)=125=$5^3$

and $\sqrt {250}<m \,\, or \, 16\leq m$----(2)

from (1) and (2) put m=16,17,18,19,20,21,22 to (*)

we get m=20 where $a=800=2^55^2$ is the only solution
 
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  • #3
Albert said:
let m=$\sqrt{\sqrt{(a+500)^2-250000}-a}----(*)$

n=$\sqrt{(a+500)^2-250000}< a+500$

$m<\sqrt{500}\,\, or\,\, m\leq 22$---(1)

$n=\sqrt {a(a+1000)}=\sqrt{a(a+2^35^3)}$

min(a)=125=$5^3$

and $\sqrt {250}<m \,\, or \, 16\leq m$----(2)

from (1) and (2) put m=16,17,18,19,20,21,22 to (*)

we get m=20 where $a=800=2^55^2$ is the only solution

Well done Albert! Thanks for participating.:)
 

FAQ: Find the sum of all positive integers a

What is the formula for finding the sum of all positive integers a?

The formula for finding the sum of all positive integers a is (n(n+1))/2, where n is the highest positive integer in the series.

How do you find the sum of all positive integers a using a mathematical series?

To find the sum of all positive integers a using a mathematical series, use the formula Sn = (n(a1 + an))/2, where n is the number of terms in the series, a1 is the first term, and an is the last term.

Can you use a calculator to find the sum of all positive integers a?

Yes, you can use a calculator to find the sum of all positive integers a by plugging in the values into the formula (n(n+1))/2 or Sn = (n(a1 + an))/2.

Is there a shortcut or trick to finding the sum of all positive integers a?

Yes, there is a shortcut or trick to finding the sum of all positive integers a. You can use the formula (n(n+1))/2 to find the sum without having to manually add all the numbers in the series.

Can you find the sum of all positive integers a if the series is infinite?

No, it is not possible to find the sum of all positive integers a if the series is infinite. The sum would approach infinity and cannot be calculated accurately.

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