using the equation of a polynomial

[Guest]

I input my data in column A = inches and B = tons. I then graphed it with an
X-Y graph and added a 2nd order Polynomial to it. The equation that is
displayed is

y=0.0123x2 + 0.411x + 0.996

I want to select an inch value and be able to calculate what the
corresponding ton value will be. Shouldn't I be able to apply the equation
above to do this? If 2 inches = 0.95 tons, what would 10 inches equal, or 50
inches. I need a math lesson!

Any help would be greatly appreciated.

Vince

 

[Guest]

Given that equation (and I'm reading into it that x is inches, y is tons),
then to use the equation with the inches from cell A2, for example, the
formula would be =0.996 + A2 * 0.411 + 0.01232 * A2 * A2.

 

[Guest]

I think you threw in an extra "2".

0.01232 * A2 * A2

or

0.0123 * A2 * A2

 

[Guest]

Thanks for the help, that was the math lesson that I needed!

 

[Ron Rosenfeld]

I input my data in column A = inches and B = tons. I then graphed it with an
X-Y graph and added a 2nd order Polynomial to it. The equation that is
displayed is

y=0.0123x2 + 0.411x + 0.996

I want to select an inch value and be able to calculate what the
corresponding ton value will be. Shouldn't I be able to apply the equation
above to do this? If 2 inches = 0.95 tons, what would 10 inches equal, or 50
inches. I need a math lesson!

Any help would be greatly appreciated.

Vince

One other caveat: you are onlyh displaying the formula to 3 decimals. This
may or may not give you an accurate result.

It may be of value to increase the display to as much as 15 decimals, depending
on the precision you require. IIRC, you right click on the text box where the
formula is displayed; select Format Data Labels; then format the number to show
15 decimals.


--ron