Quadratic Equations

[Dean]

Whats the easiest way to do them?

 

[CareBear]

ax² + bx + c = 0 ?

D = b² - 4ac

x1/2 = [ -b +/- sqrt(D) ] / 2a

If D = 0 you'll have one "real" solution with multiplicity = 2 [form: (x-a)²=0]
D > 0 you'll have two "real" solutions
D < 0 you'll have two "imaginary" solutions

 

[The Red Guy]

Solve simulatneously, which means like equate first equation to 2nd:

1 = 2

Or draw a curve.

 

[conkermaniac]

The easiest method is to factor (if you can). The next best thing is to use the quadratic formula:

      -b (+/-) sqrt(b^2 - 4ac)
x = -----------------------------
                   2a

Easy to remember, easy to use.

 

[niv]

Or use a TI-83+
Then again, I'm in calculus, so a lot of stuff like this is done by calculator to save time.

 

[The Red Guy]

Originally posted by The Red Guy
Solve simulatneously, which means like equate first equation to 2nd:

1 = 2

Or draw a curve.

Try not to use this unless you cannot solve using a criss cross method.

 

[Canuckkev]

Well...for calculus we aren't allowed our Ti-83's. It becomes difficult factoring when you get a value other than 1 for a (okay, 2 is easy...but I don't want to waste time guessing and checking on anything 4 and above...). So, doing the quadratic formula manually is much easier...

 

[Gayowulf]

Similar situation to me.

the banishment of all calculators was a major blow. I had to learn how to factor again.

and then calculus came and I wished i was in elementary school again. what I would give to have a map to colour, or maybe a story to read, instead of all this differentiation BS.

 

[The Red Guy]

Is the criss cross experimental method tough?

 

[}:8) Supermoo]

Originally posted by Mahoro
Or use a TI-83+
Then again, I'm in calculus, so a lot of stuff like this is done by calculator to save time.

I get to use TI's Derive software... it makes it even easier again, once you know what you're doing.

 

[Hobbes]

Originally posted by conkermaniac
The easiest method is to factor (if you can). The next best thing is to use the quadratic formula:

      -b (+/-) sqrt(b^2 - 4ac)
x = -----------------------------
                   2a

Easy to remember, easy to use.

USE NEWTONS METHOD!!