if x^2-2011x+1=0 is true,then waht is the value of x-2010x+2011/(x^2+1)?
$$\\If\;\; x^2-2011x+1=0 $ is true, then what is the value of $\\\\
x-2010x+\frac{2011}{(x^2+1)}\;\;?\\\\
$first$\\
x^2-2011x+1=0\\
x^2+1=2011x\\\\
$now$\\\\\
x-2010x+\frac{2011}{(x^2+1)}\\\\
=x-2010x+\frac{2011}{(2011x)}\\\\
=x-2010x+\frac{1}{x}\\\\
=-2009x+\frac{1}{x}\\\\$$
Maybe you needed more brackets in your question? I think that you probably did.
$$\\If\;\; x^2-2011x+1=0 $ is true, then what is the value of $\\\\
x-2010x+\frac{2011}{(x^2+1)}\;\;?\\\\
$first$\\
x^2-2011x+1=0\\
x^2+1=2011x\\\\
$now$\\\\\
x^2-2010x+\frac{2011}{(x^2+1)}\\\\
=x^2-2010x+\frac{2011}{(2011x)}\\\\
=x^2-2010x+\frac{1}{x}\\\\
=(x^2+1)-1-2010x+\frac{1}{x}\\\\
=2011x-1-2010x+\frac{1}{x}\\\\
=x-1+\frac{1}{x}\\\\$$
$$\\=\frac{x^2-x+1}{x}\\\\
=\frac{1011x-x}{x}\\\\
=\frac{1010x}{x}\\\\
=1010$$
I think I might have stuffed up somewhere. Plus I have a reputation for doing things the LONG way.
I'm going to look over it some more.
x2 = 2011x - 1 → x2 + 1 = 2011x
So
x^2-2010x+【2011/(x^2+1)] =
[2011x - 1 ] - 2010x + 2011/(2011x) =
x - 1 + 1/x =
[x2 - 1x + 1] / x =
[x2 + 1 - x ] /x =
[2011x - x] / x =
2010x / x =
2010 (with the restriction that x ≠ 0)
I thought about the restriction Chris but I didn't put it there because the first statement would not be true if x=0.
But like always - yours is shorter.
I started mine from the previous result where the question was wrong.
That is my excuse and I am sticking with it! LOL
(x^2-2011x+1)/x=0/x
x-2011+1/x=0
x+1/x=2011
x-1+1/x=2011-1=2010
Good job.Is it funny or not to do problem like this?if yes, i will put a problem everyday to the forum
It IS fun, quinn.......just don't make them too difficult......otherwise, it makes us look bad........
P.S ....I even had to "cheat" off Melody a bit to get that problem correct!!!! (Shhh!!!...don't tell her)
Yes I had fun with this problem quinn.
But it is better if you get the question right in the first place. I liked the Extra brackets that you put in second time round, then we know we have not misinterpreted.
I have included this problem in the next "End of Day Wrap" that i write. I invite you to read my wrap. I write one most nights.
Here is the address of yesterday's one. They are kept in with the sticky topics. :)
http://web2.0calc.com/questions/all-questions-answered-to-this-point#r294
(I don't usually include that many questions but I had not written one for a few days)
We really DID LIKE this question Quinn, you are welcome here any time