Answer:
x = 1950 units
Step-by-step explanation:
We need to maximize Profit (P(x)). We know:
Profit = Revenue - Cost
So,
[tex]P(x)=R(x)-C(x)\\P(x)=4000x-[45000+100x+x^3]\\P(x)=4000x-45000-100x-x^3\\P(x)=-x^3+3900x-45000[/tex]
This follows quadratic equation of the form [tex]ax^2+bx+c[/tex]
So, matching, we have:
a = -1
b = 3900
c = -45,000
The max occurs at the value [tex]x=-\frac{b}{2a}[/tex]
So, the level of production, x , that will maximize profit is:
[tex]x=-\frac{b}{2a}\\x=-\frac{3900}{2(-1)}\\x=1950[/tex]