What is the minimum integer value of x that satisfies the equation
⌊ x ⌋ − ⌊ x + 3 4 ⌋ = 0 ?
This problem is posed by Siam H .
Details and assumptions
The function ⌊ x ⌋ : R → Z refers to the greatest integer smaller than or equal to x . For example ⌊ 2 . 3 ⌋ = 2 and ⌊ − 5 ⌋ = − 5 .
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ok good solution.
Y cant it be 6
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Assume 6 is an answer. The floor of the square root of 6 is 2, the floor of the square root of 6+34 or 40 is 6. Because 2 is not equal to 6, 6 is not an answer.
The difference of the squares actually have to be greater than 34 in this case, since x is an integer. Assume the difference of their squares is exactly 34 and x=n^2. If this were the case, the floor of the first square root is n, and the floor of the second square root is the floor of n+1, which, since it is an integer, is itself. Since n is not equal to n+1, that would not work. Of course, if x did not have to be an integer, your case would work.
I assumed that x could be negative:D
I solved this problem using perfect squares . Let p ( n ) = n 2 be the n 'th perfect square. If p ( n ) ≤ x < p ( n + 1 ) that means that ⌊ x ⌋ = n . Since ⌊ x ⌋ has to be equal to ⌊ x + 3 4 ⌋ , we must find two perfect primes, that lie at least 3 4 apart (if they don't, ⌊ x ⌋ will be floored towards n , and ⌊ x + 3 4 ⌋ , will be floored towards ( n + 1 ) . The first pair of perfect primes with this property is p ( 1 7 ) = 2 8 9 and p ( 1 8 ) = 3 2 4 , as their difference is 3 5 . Checking the equation with x = 2 8 9 confirms, that this is a solution.
Make sure you read your solution to ensure that what you wrote is what you think you wrote.
I'm not sure why it changed from perfect squares into perfect primes . This is likely a typo that could be avoided.
x must be a perfect square.
Using mean value theorem, for some u, x < u < x+ 34
[\sqrt { x+ 34 }] -\sqrt{x} = 34/(2 \sqrt{u} ) < 1 when \sqrt{u}> 17
according to the ques , while adding 34 with x , the square root doesnt increase.how is it possible? we know that , the difference between two conjecutive integer is the sum of them. so the least difference should be odd. so , we have to calculate the next odd difference after 34 and that is 35.now how we can get 35? yes , its 18+17.so , root of x+35 should be 18.hence x is 18^2-35 or 289
Now, bases on the assumptions, we can say that, the difference of the 2 perfect squares is less than 34, hence the square root symbol. So, we need to find 2 perfect squares that have a difference of 34 and/or less. The 2 numbers are 256 and 289. Therefore, the answer is 289.
Now, let's do this algebraically. It's basically y = x 2 ; ( x + 1 ) 2 − x 2 ≥ 3 4 . Basically, when solved, we get y = 17, so x = 289.
jst see the perfect square after which adding 34 to it stops the result before the next perfect square as it is 289. ... 289+34 is less than 364 that is the next
don't u mean 324 not 364
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Since we have to find out the square roots of x and ( x + 3 4 ) , basically we want to find two consecutive numbers whose squares don't differ by less than 3 4 . Let y and y + 1 be the consecutive numbers, so the difference of their squares is
( y + 1 ) 2 − y 2 = 2 y + 1
Now, we want this equal to 3 4 , which yields y = 1 6 . 5 . Now let x = y 2 . But y 2 is not an integer. The closest number to 1 6 . 5 whose square is an integer is 1 7 . So y = 1 7 and hence x = y 2 = 2 8 9 .