4(x+ [)1042xl 9. Let = y x(x + 3)5 Find y'(l) (logarithmic differentiation is easiest). 10. The monthly prot rate (in thousands of dollars per month) from sales of a seasonal item is modeled by P0) = 20 10 cos 2%, where (is the time in months since January 1\". Is monthly prot increasing or decreasing at the end of July (I = 7 ), and at what rate