Let f ( x ) be a function that satisfies
f ( 2 0 1 4 + x ) = f ( 2 0 1 4 − x ) .
If f has exactly 3 roots being α , β , γ , what is the value of α + β + γ ?
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The equation is symmetric about x = 2 0 1 4 .
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When is an equation symmetric??
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When it's behaviour is symmetric about a line or a point.
The equation implies that if (2014-a) is a root,(2014+a) must also be a root. However, the only way for there to be an odd number of roots is when a=0 , otherwise there will be another distinct root. Thus one of the roots is 2014 and the rest are (2014-x) , and (2014-x) for some real x. Those two roots add up to 4028. Thus the answer is 6042.
Plagiarism
the function is symmetric about 2014 and 1 root is 2014
We have f ( x + 2 0 1 4 ) = f ( 2 0 1 4 − x ) f ( x ) = f ( 4 0 2 8 − x ) So whenever a is a root of f ( x ) 4 0 2 8 − a is also a root of f ( x ) let b be another root of the function which is not equal to a.This implies (4028-b) is also another distinct root...So the equation will have 4 roots instead of 3 which is a contradiction... So the only possibility is that all the roots must be equal so a = 4 0 2 8 − a ...and a = 2 0 1 4
So the sum of all the roots is 2 0 1 4 ∗ 3 = 6 0 4 2
OOPs...Abandon this solution I made an exaggerated assumption that all the roots must be equal but it is not so...It should have been actually b = 4 0 2 8 − b and the other two roots would have been a,2014-a....This condition would equally suffice....and of course it's a more generalized one....
YEAH- THE SOLUTION IS BIT TRICKY.NEVERTHELESS GOOD LOGIC.
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The equation implies that if ( 2 0 1 4 − a ) is a root, ( 2 0 1 4 + a ) must also be a root. However, the only way for there to be an odd number of roots is when a = 0 , otherwise there will be another distinct root. Thus one of the roots is 2014 and the rest are ( 2 0 1 4 − x ) , and ( 2 0 1 4 + x ) for some real x . Those two roots add up to 4028. Thus the answer is 6042.