Math Help - rate of change

hi, i'm starting to look at work on rates of change and was wondering if someone could explain something to me.

the example question goes like this:

the volume, of water is given by . find the rate of change of volume with respect to time after 0.5 hours

it then goes on to and explains that:

when t = 0.5 after 0.5 hours the volume is increasing at a rate of

i don't understand where the power of minus 1 comes from?

can someone please explain this? thankyou

per hour! (same as /h)

i understand that h stands for per hour. i meant the "to the power of minus 1" part. why is it to the power of minus one?

also how do you write it in latex so that the 1 appears small and at the top like in . it comes out big with minus 1
cheers

use the 'hat' symbol (shift 6?) like in excel etc. i.e. h^{-1} oh yes and use curly braces if the power contains more than one character

h means hour, power minus one means per

ah i see. thanks