Cooling process - Exponential functions

[Svensken]

Homework Statement

Hello i am doing a cooling experiment and i want to know the following:

y=28.49e^(-0.03890*800) +26.51 (note the 26.51) is not part of the exponential.

What is y? and I was wondering whether this would go ever go through the x axis?

Thanks people!

Homework Equations

T=T(initial)*e^(-kt)+T(room)

The Attempt at a Solution

I have been putting the info into my calculator and i just can't seem to be able to graph it (TI-84) and from my knowledge of exponentials i don't think that an exponential like this can be below the x axis, but i may very well be wrong.

Thanks again
-Svensken

 

[rock.freak667]

When y=0

Ae^kx+B= 0 ⇒ e^kx=-B/A

and e^kx is never less than zero for all values of x. Thus it does not cross the x-axis.

 

[Svensken]

Thanks mate!