hi all,

im confused with the way an answer is given in reciprocal cm format the questions was:

The temperature measured at a distance is given by:

for distances

Find the temeparture gradient (i.e. the rate at which temperature decreases with distance) 10cm from the flame.

my answer was

, where t(emp), d(istance)

to 3 sf

but the book (Edexcel A level maths} gives the answer as

can someone please explain what the reciprocal cm is all about.

thanks.