There is a sequence which has the first 3 terms as
1 , 4 2 0 1 , 9 4 0 9 5 , … .
The 99th term has all but one digits. Call the missing digit x . Find the reverse of the digits of x th term.
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That is not the definition of the word "palindrome". The correct term should be "reverse the digits".
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I thought palindrome could be defined as what I wrote it as. Sorry, I'll change the wording.
yes...you are right.👍
Can someone explain how you got the fact that 99^10 doesn't contain the digit 6? I had no idea how to work it out, eventually, I used a calculator, which felt like cheating.
I tried using representing 99 as (100 - 1) to try and make it easier to multiply, but that didn't help too much
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You could use the algorithm that is often used by computer software, which is essentially a kind of divide-and-conquer, if you will.
Brilliant problem. The word palindrome gave it away. Or else I would never have figured out the sequence. Reversing the digits of the numbers in the given sequence, we get 1 , 1 0 2 4 , 5 9 0 4 9 Observe that they are all 10th powers of natural numbers 1 1 0 , 2 1 0 , 3 1 0 Since the 99th term is to be found, use wolframalpha to find the value 9 9 1 0 = 9 0 4 3 8 2 0 7 5 0 0 8 8 0 4 4 9 0 0 0 1 Observe that the digit 6 is missing. So the 6th term will be the reverse of 6 1 0 But the question asks us to find the palindrome of the 6th term, which will simply be 6 1 0 = 6 0 4 6 6 1 7 6
Confession: I used oeis.org to identify the sequence. (I'd still be peering at this problem tomorrow if I hadn't.)
Here f calculates terms in the sequence in the form of strings rather than integers. I verify that the digit 6 is not in the string for f ( 9 9 ) . Then I calculate f ( 6 ) and its value with digits reversed.
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Let f(z) be a function defined on z such that it forms the palindrome of z. E g : f ( 1 2 3 4 ) = 4 3 2 1 We have, 1st term = f ( 1 1 0 ) = 1 2nd term = f ( 2 1 0 ) = 4 2 0 1 3rd term = f ( 3 1 0 ) = 9 4 0 9 5 . . . 99th term = f ( 9 9 1 0 )
From Binomial theorem,on expansion of 99th term,it is found that it doesn't has 6 => x = 6 6th term = f ( 6 1 0 ) Hence,Palindrome of 6th term is f ( f ( 6 1 0 ) ) = 6 1 0 = 6 0 4 6 6 1 7 6