magneto1
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Let $x=a$ be a solution of the equation $x^{2012}-7x+6=0$. Find all the possible values for: $1+a+a^2+\cdots+a^{2011}$.
The discussion focuses on the polynomial equation $x^{2012}-7x+6=0$ and seeks to determine the possible values of the sum $1+a+a^2+\cdots+a^{2011}$, where $a$ is a root of the polynomial. Participants confirm the correctness of the proposed solutions, indicating a collaborative effort to validate the findings. The analysis of the polynomial's roots and their implications on the geometric series sum is central to the conversation.
PREREQUISITESMathematicians, students studying algebra, and anyone interested in polynomial equations and their properties.
magneto said:Let $x=a$ be a solution of the equation $x^{2012}-7x+6=0$. Find all the possible values for: $1+a+a^2+\cdots+a^{2011}$.
anemone said:My solution:...
anemone said:My solution:
We're told $x=a$ is a solution of the equation $x^{2012}-7x+6=0$, therefore we have $a^{2012}-7a+6=0$.
It can be rewritten as
$a^{2012}-1-7a+6+1=0$
$a^{2012}-1-7a+7=0$
$(a^{2012}-1)-7(a-1)=0$
$(a-1)(a^{2011}+a^{2010}+\cdots+a+1)-7(a-1)=0$
$(a-1)(a^{2011}+a^{2010}+\cdots+a+1-7)=0$
So the value of the expression $1+a+a^2+\cdots+a^{2011}$ could be either 2012 or 7.