# Math Quiz question help

• Sep 14th 2005, 06:49 PM
zatfish
Math Quiz question help
ok, since my teacher isnt doing a very good job at explaining this we need to know for quizzes, I was wondering if you guys can help me.

here are some of the questions om stuck on

1.Find the limit if it exists

Lim log (x-4)
x->4 5

2.Find the derivatives

g(x)=ax+b/cx+d, where a, b, c, and d are constants with ad - bc /= 0

3.

h(x)= x - x/\3

thx
• Sep 15th 2005, 01:20 AM
hoeltgman
1. $\lim_{x \rightarrow 4} \log_5 (x-4) = - \infty$
You try to find log (0) which is $- \infty$

2. $g'(x) = \dfrac{ad - bc}{(cx + d)^2}$
It's a simple fraction either you use the formula for fractions with terms above and under the fraction, or you split it up into a multiplication between the upper terms and the rest of the fraction. And you calculate them separately. Both ways work rather good. Don't let you be confused by the a,b,c and d. Look at them if they were simple numbers. All you need to do is watch out for the x.

3. $h'(x) = 1 -3x^2$ It's a simple polynom. Derivate term by term. That's it.
• Sep 18th 2005, 05:54 PM
zatfish
thx for the help alot.