Find the Limit

• November 7th 2008, 10:07 AM
beachbunny619
Find the Limit
1)lim (4x-8)^5/2
x->6

2)The sales of a new product over a period of time are expected to follow the relationship

S(x)=14000 x² /7 x² +2000
where x is the amount of money spent on advertising

What is lim S(x)=
x-> ∞

Thank you.
• November 7th 2008, 10:21 AM
james_bond
For the second one: $S(x)=\frac {14000\cdot x^2}{7000\cdot x^2+2000}=\frac {14000}{7000+\frac {2000}{x^2}}\longrightarrow \lim_{x\rightarrow\infty}=\frac {14000}{7000+0}=2$
• November 7th 2008, 03:14 PM
beachbunny619
That's not right.
• November 7th 2008, 03:22 PM
Plato
There is a simple typo in that answer.
$S(x)=\frac {14000\cdot x^2}{7\cdot x^2+2000}=\frac {14000}{7+\frac {2000}{x^2}}\longrightarrow \lim_{x\rightarrow\infty}=\frac {14000}{7+0}=2000$