Math Is Fun Forum

willis

Member

Registered: 2010-02-24

Posts: 7

Sketch equation

Hi can anyone sketch the following equation?

Y = x² + 3x - 4

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sketch equation

Hi willis;

To do it by hand: Make the table and then plot each point and draw a smooth line through them.

x  -5    -4      -3    -2     -1    0      1     2     3           
----------------------------------------------------------
y  6      0      -4    -6     -6    -4     0      6    14 

If you did it right it will look something like this:

http://www.mathsisfun.com/graph/functio … max=20.424

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

willis

Member

Registered: 2010-02-24

Posts: 7

Re: Sketch equation

Thanks heaps helped alot

Anakin

Member

Registered: 2009-10-04

Posts: 145

Re: Sketch equation

As only a SKETCH is being requested, you can factor it as follows:
y= x^2+3x-4
y= (x+4)(x-1)

The zeros are x=-4 and x=+1. The leading co-efficient is positive so it opens up. With that much information, you should be able to sketch the parabola.

Last edited by Anakin (2010-02-25 11:31:40)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Sketch equation

Hi Anakin;

Yea, that looks cleaner and is a lot less work.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

soroban

Member

Registered: 2007-03-09

Posts: 452

Re: Sketch equation

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