Absolute Value Question. Seriously need help.
\[[x / |x ^{2} -2|] - (1/5)\]
sorry additional \[\ge 0\]
I am working on it
okay cool, thanks
is it? \[\LARGE {x\over |x^2-2|}-\frac15\geq 0\]? (the question :) )
YESSS that is the question
lol , I'll "try " it too... although I don't promise anything :B haha..
... well: \[ \LARGE {x\over |x^2-2|}-\frac15\geq 0 \] \[ \LARGE {x\over |x^2-2|}\geq \frac15 \quad \quad |\cdot 5\] \[ \LARGE {5x\over |x^2-2|}\geq 1 \quad \quad \cdot |x^2-2|\] \[ \LARGE 5x\geq |x^2-2 |\] I'm not sure something here.. Let me work on it. ... also here's what wolframa says :) http://www.wolframalpha.com/input/?i=%28x%2F%7Cx%5E2-2%7C%29-1%2F5%3E%3D0
before starting to solve it by quadratic equations: let's see what the master tells us. I'm sure @satellite73 can handle this.
seems not to be here... anyway , This is what I've got: from: \[\LARGE 5x\geq |x^2-2|\] we have: \[\LARGE x^2-2\leq 5x \quad ----[1]\] and \[\LARGE x^2-2\geq -5x \quad -----[2]\] [1] \[\Large x^2-2-5x\leq 0\] \[\Large x^2-5x-2\leq 0\] now using the quadratic formula: \[\LARGE {x_{1/2}} = \frac{{ - b \pm \sqrt {{b^2} - 4ac} }}{{2a}}\] I can't get Integers as wolframa said :( ...
yes, because the answers are in decimals
\[\LARGE {x_{1/2}} = \frac{{ - ( - 5) \pm \sqrt {25 - 4( - 2)} }}{2}\] \[\LARGE {x_{1/2}} = \frac{{ 5 \pm \sqrt {33 } }}{2}\] And here's the problem :( ... really ?? so let's see ! ;)
\[\LARGE {x_1} = \frac{{5 - 5.74}}{2} = \frac{{ - 0.74}}{2} = - 0.37\]
what are multiple choices ?
sorry there's not \[\LARGE x_1=-0.37\] but \[\LARGE x_1\leq -0.37\]
and for the second one [2] we have: \[\LARGE x^2-2\geq -5x\] \[\LARGE x^2+5x-2\geq 0\] using the quadratic formula we have: \[\LARGE {x_{1/2}} \geq \frac{{ - b \pm \sqrt {{b^2} - 4ac} }}{{2a}}\] \[\LARGE {x_{1/2}} \ge \frac{{ - 5 \pm \sqrt {33} }}{2}\] \[\LARGE {x_{1/2}} \ge \frac{{ - 5 \pm 5.74 }}{2}\] \[\LARGE {x_{1}} \ge \frac{{ - 5 - 5.74 }}{2}\] \[\LARGE {x_{1}} \ge \frac{{ - 10 .74 }}{2}\] \[\LARGE {x_{1}} \ge -5.37 \]
and x_2 ...
sdfsd \[ \LARGE {x_{2}} \ge \frac{{ - 5 + 5.74 }}{2} \] \[ \LARGE {x_{2}} \ge \frac{{ 0.74 }}{2} \] \[ \LARGE {x_{2}} \ge 0.37 \]
sorry about "sdfsd" lol ... @fatinatikah still there? :)
yes yes im still here, im trying the solution u gave me :)
do you mind to post multiple choices? :)
@fatinatikah
\[\frac{x}{|x^2-2|}\geq\frac{1}{5}\] \[5x\geq |x^2-2|\] so one thing we know for sure is that \(x\geq0\)because the right hand side is positive. also we know if \(0<x<\sqrt{2},x^2-2<0\) and so \(|x^2-2|=2-x^2\)so on that interval you need to solve \[5x>2-x^2\] get \[x>\frac{-5+\sqrt{33}}{2}\]
if \(x\geq\sqrt{2}\) we need so solve \[5x>x^2-2\] and get \[x<\frac{5+\sqrt{33}}{2}\]
therefore you answer is \[\frac{-5+\sqrt{33}}{2}\leq x\leq \frac{5+\sqrt{33}}{2}\]
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