Here is my problem and I just can't get the correct formula.

Suppose http://edugen.wiley.com/edugen/share...=1254263519632 the number of cases of a disease, is reduced by 11% each year.

(a)If there are initially 10,000 cases, express http://edugen.wiley.com/edugen/share...=1254263519632 as a function of http://edugen.wiley.com/edugen/share...=1254263519632 the number of years elapsed.

Help please.