2y^2+2y+1=0

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- Aug 21st 2008, 10:23 AMPeyton Sawyerquadratic formula
2y^2+2y+1=0

- Aug 21st 2008, 10:25 AMChop Suey
The quadratic formula is:

$\displaystyle y = \frac{-b\pm\sqrt{b^2-4ac}}{2a}$

What are a, b, and c? Well, you should know that:

$\displaystyle 2y^2+2y+1 = ay^2 + by + c$ - Aug 21st 2008, 10:29 AMChris L T521
- Aug 21st 2008, 10:31 AMPeyton Sawyer
my answers arnt even close to these

a. {(± √3)/2}

b. { -1, 0 }

c. {(1 ± √3)/2}

d. {(-1 ± √3)/2}

e. { 0, 1 } - Aug 21st 2008, 10:36 AMChris L T521
Just check and make sure you typed out the equation correctly. I think you have a missing minus sign somewhere. The way you gave us the equation implied that there was no real solution. If this equation you gave us is correct, then none of these choices are correct.

--Chris - Aug 21st 2008, 10:41 AMPeyton Sawyer
this is the original

2y^2+ 2y=1 - Aug 21st 2008, 10:43 AMChop Suey
In this case, you rearrange it to:

$\displaystyle 2y^2 + 2y - 1 = 0$

And use the quadratic formula to find the two roots. - Aug 21st 2008, 10:46 AMmathceleb
Answer is d.

I need to build an extra piece on the lesson here:

Quadratic Equation

But you can follow the math 1/2 way down and see that you get to:

-2 ± $\displaystyle \sqrt{12}$/4

Then Factor out a 2 from the top, which, for the second term is the simplifying the square root. - Aug 21st 2008, 10:48 AMPeyton Sawyer
okay i got

-1 plus/minus sq root 3/2 - Aug 21st 2008, 10:52 AMChop Suey
$\displaystyle \frac{-1\pm\sqrt{3}}{2}$

Then yes, you are right.