Help with excel (how to put infinity as a value)

[Sebastian]

I have a homework assignment where I have to take a time value to infinity. Here is the data:
Ca(gal/liter) .1823 .1453 .1216 .1025 .0795 .0495
Time (min) 0 36 65 100 160 Infinity
(colors match up with values. Eg. black time goes with black Ca
I need to do a semilog plot, and I was wondering how I could represent infinity as a value on the graph. Anyone know?

 

[Dancingwllamas]

What class is this? It sounds to me like you are going to want to use limits to figure out the answer.

I don't know how to do that in Excel or if it even can.