Using the weekly sales function, find the rate at which weekly sales are changing
2,675
Let us define the rate at which weekly sales are changing to be $\frac{dS}{dT}$
Let us define the rate at which weekly advertising costs are changing to be $\frac{dx}{dT}$
Let us define the change in weekly sales with respect to change in advertising costs to be $\frac{dS}{dx}$
$S=1980+45x+.65x^2$
$\frac{dS}{dT}$ = $\frac{dS}{dx}$*$\frac{dx}{dT}$
$\frac{dS}{dT}$ = $(45+1.3x)$*$\frac{dx}{dT}$
Now evaluate $\frac{dS}{dT}$
at x = $8400, $$\frac{dx}{dT}$ = 1250
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Hayley
Updated on December 06, 2020Comments

Hayley almost 3 years
Using the weekly sales function $s=1980+45x+0.65x^2$ with $x$ representing weekly advertising costs, find the rate at which the weekly sales are changing when the weekly advertising costs are 8400 dollars and these costs are increasing at a rate of 1250 dollars per week

Hayley almost 10 yearsHonestly, Nothing. I don't even comprehend it. :(

kaine almost 10 yearsYou know how to do derivatives?

Hayley almost 10 yearsI only know how to do like very simple derivative functions


Hayley almost 10 years13,706,250? is that right ?

kaine almost 10 yearsthat is the correct value, yes.