hopelynnwelch
Junior Member
- Joined
- Jan 16, 2015
- Messages
- 60
Limit as x goes to 9 of (sqrt(x) - 3)/(x-9)
To figure this out algebraically I would sub 9 in for x but I can't because that would make the function undefined. So I guess what I think I should do is multiply the entire function by the conjugate of the numerator.
That leaves me with (x-9)/(x(sqrt(x))+3x-9(sqrt(x))-27)
But if I sub 9 into this, my function is still undefined.
I could make a table and sub in numbers close to 9 from a negative and positive direction. For example 8.9, 8.99, 8.999 and 9.1, 9.01, 9.001.
But would that be calculating algebraically? Is there some way of manipulating this function I am just not seeing?
It has been 5 years since I took Functions for Calc and I am now taking calc I and II (I had babies) So my algebra is pretty rusty...
To figure this out algebraically I would sub 9 in for x but I can't because that would make the function undefined. So I guess what I think I should do is multiply the entire function by the conjugate of the numerator.
That leaves me with (x-9)/(x(sqrt(x))+3x-9(sqrt(x))-27)
But if I sub 9 into this, my function is still undefined.
I could make a table and sub in numbers close to 9 from a negative and positive direction. For example 8.9, 8.99, 8.999 and 9.1, 9.01, 9.001.
But would that be calculating algebraically? Is there some way of manipulating this function I am just not seeing?
It has been 5 years since I took Functions for Calc and I am now taking calc I and II (I had babies) So my algebra is pretty rusty...