SOLUTION: 1) if 2^n + 1 is a prime show that n is a power of 2. it indicates directly to fermat numbers but i can't connect this question with fermat numbers. 2) a printer numbers all the

Question 253439: 1) if 2^n + 1 is a prime show that n is a power of 2.
it indicates directly to fermat numbers but i can't connect this question with fermat numbers.
2) a printer numbers all the pages of a book starting with 1 and uses 3189 digits in all.how many pages does the book have?
i have asked 2 questions which is within the limit. please if u can , answer them.
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
http://en.wikipedia.org/wiki/Fermat_number#Other_theorems_about_Fermat_numbers
The proof is there.

1-9=9
10-99=2*90
100-999=3*900
2700
180
9
2889
3189-2889=300
300/4=75
1000+74=1074

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