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Determine which real numbers exceed their reciprocals by exactly 1 .

User IsuPatches
by
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1 Answer

6 votes

Let n represent one such number. Then:


n - 1/n = 1 (the difference between the number n and its reciprocal is 1).

Solve for n: Multiply all three terms by n, to remove fractions:


n^2 - 1 = n, or n^2 - n - 1 = 0

Solving this for n:

-(-1) plus or minus √(1-4[1][-1])

n = ---------------------------------------------

2

1 plus or minus √5

= ----------------------------------

2

or....

x = (1+√5)/2 or x = (1-√5)/2

User Navid Shad
by
7.9k points

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