Extending a number to a square

Given any finite sequence of digits, is it true that there's always a perfect square which begins with that sequence?

For example: this is true for the sequence ( 1 , 5 , 6 , 5 ) (1,5,6,5) because 1565001 = 125 1 2 1565001=1251^2 .

No Yes

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Alex Li
Aug 15, 2018

Given a sequence S, let's find a perfect square that begins with that sequence.

Suppose S = 6 , 9 , 1 , 1 S = {6,9,1,1}

Pick any number between 6911 \sqrt{6911} and 6912 \sqrt{6912} with a finite number of number after the decimal points. (Clearly, it must exist. In this case, we can choose 83.135) Squaring this number will lead to a number that starts with 6911. However, it's not an integer. To fix this, multiply by 10 until it is. Now, the resultant number's square will begin with the sequence.

83135^2 = [6911]428225.

This method will work with any sequence, so the statement is true in general.

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...