Hi,

I am trying to work out some quadractic equations when I compare the my answer to the answer book it is wrong. I even typed in the exact example they gave me. My calculator screen is attached is it in the right settings?

Thanks

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- Sep 26th 2008, 02:50 AMTheHour[SOLVED] Quadratics setting on cacluator
Hi,

I am trying to work out some quadractic equations when I compare the my answer to the answer book it is wrong. I even typed in the exact example they gave me. My calculator screen is attached is it in the right settings?

Thanks - Sep 26th 2008, 05:10 AMmasters
- Sep 26th 2008, 06:12 AMTheHour
I need the calculator for the formula

http://upload.wikimedia.org/math/3/e...a3bb558916.png

When I substitute a, b and c the answer is I get on my calculator is different to the answer in the answer book I know the theory is correct. Would you like to see my workings

Thanks - Sep 26th 2008, 06:18 AMmasters
- Sep 26th 2008, 06:40 AMTheHour
Here it is

Thanks - Sep 26th 2008, 07:09 AMmasters
- Sep 26th 2008, 07:20 AMTheHour
So its my calculator as I worked out

$\displaystyle \frac{-5+\sqrt{17}}{2}$

$\displaystyle \frac{-5-\sqrt{17}}{2}$

on my calculator and it gave me the results in the image above. The settings on the caluclator are in my first post, im sure I have reset the settings by mistake. Looks like my method is fine though just the working out wich wasn't even done by me :)

Thanks - Sep 26th 2008, 07:26 AMmasters
You have to be careful when you enter things in a calculator. You probablly did not pair all your parentheses. Try it this way:

Be sure to put the entire numerator in parentheses before you divide by 2.

My solutions in Post #6 are correct. What does your book say? - Sep 26th 2008, 07:58 AMTheHour
You where correct as the answers say -0.438 or -4.562.

While typing this I remember the way I am working it out I need brackets, im not typing it in as a fraction as you did, im just doing it as one line, doh. All fixed

Many Thanks, for your help