What Do You Learn From Quadratic Equations

Solving Quadratic Equations

I'm looking for the equation of a demand curve, which is usually negative sloping, i.e. y = -x. Well, at least that is how it should look. However, I know that y = -x is a linear equation, and that's not exactly what I need. I guess it could be negatively exponential, but I just don't know. Perhaps it might help to give you a few examples of the points on the curve (points are in x:y format)

1) 1,000:400
2) 1,500:300
3) 2,400:200
4) 4,000:100

I should think that the y-intercept would be around 800. It doesn't matter very much whether the curve touches the x-axis, but I would think that the curve would start approaching it around 8,000 or 9,000.

This is actually the curve that I'm trying to find the equation for. Not only that, but then instead of having it in the format of y = ... , I would need it in the format x = ... If you could show me how to find that, I would appreciate it very much.

Answer:

The curve looks like the top right of a circle as I visualise it. You will find it difficult though to work out the exact equation of the curve.

Perhaps this may help put it in the form x=ay^2+bx+c:

y=ax^2+bx+c

y-c=ax^2+bx

You then have to complete the square:

y-c=sq( rt(a)x+(b/(2rt(a)) ) - b^2/4a (test it by multiplying it out. I may have made a mistake)

y-c+b^2/4a= sq( rt(a)x + (b/2rt(a)) )

rt( y-c+b^2/4a ) =rt(a)x + (b/2rt(a))

rt( y-c+b^2/4a)- (b/2rt(a)) = rt(a)x

<rt( y-c+b^2/4a ) - (b/2rt(a)) >/ <rt(a)>= x

A bit difficult to follow, so suggest writing it out on paper. Have used sq to mean ^2 at times and obviously rt(x) to mean the square-root of x. May be some mistakes here so apologise in advance if so, but gives the general idea on how to isolate x

A Data-Based Model to Predict Postsecondary Educational Attainment ... - RedOrbit

A Data-Based Model to Predict Postsecondary Educational Attainment ... RedOrbit, TX - Jun 6, 2008 Because no variables exhibited quadratic tendencies, variables were defined as ordinal or interval in the following equations. Only small changes in the ...

Sandra Rettle leading a new era in the West Indies - ITTF

ITTF	Sandra Rettle leading a new era in the West Indies ITTF, Switzerland - Jun 15, 2008 Now, I’m no Euclid or Pythagoras but almost forty players and four tables is some quadratic equation. “The coaches also visit the outlying districts because ...

Yale schools have made huge strides - Port Huron Times Herald

Yale schools have made huge strides Port Huron Times Herald, MI - Jun 15, 2008 But our students can do so much more in a world that expects more. Our seventh-grade math students learn about slope and graphing linear equations. ...

Let's teach pupils about real life - Irish Independent

Let's teach pupils about real life Irish Independent, Ireland - Jun 7, 2008 As someone who has long despaired of the relevance of the Leaving Certificate to the life that comes after it, I was heartened to learn that the National ...

Math whiz eases onto the fast track - Baltimore Sun

Math whiz eases onto the fast track Baltimore Sun, United States - Jun 8, 2008 "Do you know what the quadratic equation is?" Benjamin asked. She stared back blankly. "Don't worry about it. You'll learn about it later," he said. ...

Math camp gives girls equation on how - Greeley Tribune

Math camp gives girls equation on how Greeley Tribune, CO - Jun 20, 2008 As the math professor wrote a quadratic equation on the chalkboard, girls around the room volunteered correct numbers to plug into the complex formula. "You ...

Derbyshire: June Diary - National Review Online Blogs

Derbyshire: June Diary National Review Online Blogs, NY - Jul 1, 2008 The students have to do most of the work. The only way to learn math is to grind your way through endless drills. You want to understand quadratic equations ...

Untitled

being th random freako, pls tag at my blog. thanks. eneri. i send that to: LLERRAD. jen. junyan. alicia. kerrhui. cherie. kelmond. junwei. weijian. clarine. jo-elle. and who replied to my oh-so-scary order? I DONNO. haha. as i was apperaring offline. :D I LOVE TREATS. remember that. school was fun today. it was fun ytd too. HAHAHAH, i sound like a primary kid! cute and innocent. :D YTD [rainbow tuesday] PE was ... stupid. haha. we wasted our time. but we played volley! lol i was screaming A