# Math Help - Test Thurs having probs with some review ?

1. ## Test Thurs having probs with some review ?

Ok Im in business calculus and I have a test on thurs. Im having some probs on my review was wondering if someone could help me solve these. some seem easy I just cant figure them out maybe someone can show me an easy step
1. BLAH BLAH type of products are given by S(t)=60-80e^-.1t where t represents time in years. Find the rate of cange i n sales at the time when t=3
2. Diffrentiate
Find f'(x) for f(x)= x/7x-5?
3. Find f'(x) for f(x)8e^+4ln(x^3)

2. Originally Posted by ls1ramair19
Ok Im in business calculus and I have a test on thurs. Im having some probs on my review was wondering if someone could help me solve these. some seem easy I just cant figure them out maybe someone can show me an easy step
1. BLAH BLAH type of products are given by S(t)=60-80e^-.1t where t represents time in years. Find the rate of cange i n sales at the time when t=3
2. Diffrentiate
Find f'(x) for f(x)= x/7x-5?
3. Find f'(x) for f(x)8e^+4ln(x^3)
$S'(t) = -80(-.1)e^{-1.1t}$

$S'(t) = \frac{8}{e^{1.1t}}$