[FONT=&]The price [/FONT]

*P*of an electronic component is known to be:

*2*

*P(c) =**- 18/*

*c**where*

*c**is the manufacturer's cost to produce it*

*c**The cost*

*.**is a function time*

*c**according to*

*t**= 9 + 3/*

*c(t)**Determine the rate of change of price with respect to time (*

*t**dP*/

*d*at time

*t*)*= 3 years*

*t*

*.*