## help graphs

### south lanarkshire jag

Posted 11 November 2005 - 12:40 PM

can anyone help me with drawing the graph of 2x2(2= squared) -2x?

thanks

SLJ

### *sofax*

Posted 11 November 2005 - 12:42 PM

what's the equation I'm confused by the way you have written it!

### south lanarkshire jag

Posted 11 November 2005 - 01:04 PM

(2x) all squared Subtract 2x

it's for a friend

### *sofax*

Posted 11 November 2005 - 02:00 PM

with the x being squared it sounds to me like it should be an up right parabola!

### aldo

Posted 11 November 2005 - 03:05 PM

You can use software such as Excel (or your calculator) taking set values of x and calculating the corresponding y value.

I have attached what it should look like.

### dfx

Posted 11 November 2005 - 06:12 PM

Just a quick run through of teh sketching procedure:

x = 0 or x = 1.

So now you know it cuts the x-axis through 0 and 1.

It cuts the y-axis when x = 0, so y = 0 also.

Lastly, find the turning points by differentiating and setting the derivative = 0.

So the x-coordinate of the turning point is x = 1/2 . For the y-coordinate:

So the turning point is (1/2 , -1/2).

Finally, you know its a parabola because it's a degree 2 polynomial, and that it has a minimum turning point (i.e. it's U shaped because the coefficient of x is positive).