Saturday, March 26, 2011

x1 and x2 are solutions of x^2-x+1=0. What is the value of the sum (x1^2-x1)^1000 + (x2^2-x2)^1000 ?

We know the fact that the solution of an equation,
substituted into equation, it cancels out the
equation.


We'll substitute the solutions of the equation
into the given equation:


x1^2 - x1 + 1 =
0


x1^2 - x1 = -1We'll raise to the power of 1000 both
sides:


(x1^2-x1)^1000 =
(-1)^1000


(x1^2-x1)^1000 = 1
(1)


x2^2 - x2 + 1 = 0


x2^2 -
x2 = -1We'll raise to the power of 1000 both
sides:


(x2^2-x2)^1000 =
(-1)^1000


(x2^2-x2)^1000 = 1
(2)


We'll add (1) and
(2):


(x1^2-x1)^1000 + (x2^2-x2)^1000 = 1 +
1


(x1^2-x1)^1000 + (x2^2-x2)^1000 =
2


The value of the sum =
2.

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