# Secant lines...completely lost.

• Aug 31st 2009, 11:13 AM
Voluntarius Disco
Secant lines...completely lost.
a. For each function find the average rate of change of f from 1 to x.
b. Use the result from part (a) to compute the average rate of change from x=1 to x=2. Simplify.
c. Find an equation fo the secant line containing (1, f(1)) and (2,f(2)).

My work:
1-3x+2/(x-1)=3x+1/(x-1)

Here is where I'm getting stuck mostly. I don't understand how that could be the rate of change of f from 1 to x. I feel that if I can understand part a I can understand the rest of the parts.
I also can't see any way to factor this.
If anybody could help I would be very appreciative.
Thanks! =)
• Aug 31st 2009, 03:55 PM
skeeter
Quote:

Originally Posted by Voluntarius Disco
a. For each function find the average rate of change of f from 1 to x.
b. Use the result from part (a) to compute the average rate of change from x=1 to x=2. Simplify.
c. Find an equation fo the secant line containing (1, f(1)) and (2,f(2)).

My work:
1-3x+2/(x-1)=3x+1/(x-1)

Here is where I'm getting stuck mostly. I don't understand how that could be the rate of change of f from 1 to x. I feel that if I can understand part a I can understand the rest of the parts.
I also can't see any way to factor this.
If anybody could help I would be very appreciative.
Thanks! =)

you know, it would help to know what f(x) is ...
• Sep 1st 2009, 05:02 AM
HallsofIvy
Quote:

Originally Posted by Voluntarius Disco
a. For each function find the average rate of change of f from 1 to x.
b. Use the result from part (a) to compute the average rate of change from x=1 to x=2. Simplify.
c. Find an equation fo the secant line containing (1, f(1)) and (2,f(2)).

My work:
1-3x+2/(x-1)=3x+1/(x-1)

There is NO "work" shown here, just an equation. In particular, a skeeter said, without know what function you are working with, this is meaningless.

Quote:

Here is where I'm getting stuck mostly. I don't understand how that could be the rate of change of f from 1 to x. I feel that if I can understand part a I can understand the rest of the parts.
I also can't see any way to factor this.
If anybody could help I would be very appreciative.
Thanks! =)
• Sep 1st 2009, 06:33 PM
pacman