Graphing logarithm and natural log

alyren said:
graph the function
1.f(x) = 2-ln(x+4)

2. f(x) = (e^3x)-3
Click to expand...

Are you supposed to use a graphing calculator?

Please show us your work, indicating exactly where you are stuck - so that we may know where to begin to help you.
 
i want to know how to solve it without calculator.

first i switch x and y
x=(e^3x)-3

then +3 both side
x+3=e^3x

this is where i stuck.
 
alyren said:
i want to know how to solve it without calculator.

What are you trying to solve ?

We do not need to solve anything, to graph function f.

first i switch x and y WHY ?

x=(e^3x)-3 ? This does not show "switch x and y"

All you did was replace the symbol f(x) with the symbol x, and that does not make sense.

f(x) does not equal x.
Click to expand...

I do not understand what you're trying to do.

If you are trying to graph function f by hand, you could pick some values from the domain and make an xy-table of coordinates.

Plot some points, and connect them with a smooth curve.

 
sorry about typo

x=e^(3y)-3

+3 both side

x-3=e^(3y)

now how do i get rid of e and get y by it self?
 
alyren said:
sorry about typo

Do not be sorrowful; be diligent, instead. 8-)

Use the [Preview] button next to the [Submit] button to proofread your typing before posting it.

x = e^(3y) - 3

+3 both side

x - 3 = e^(3y)

If we add 3 to x, the result is not x - 3.

how do i get y by [itself] ?

Take the natural logarithm of both sides first, then divide both sides by 3.
Click to expand...

Your approach makes me think that you're searching for the inverse function of f(x) versus graphing f(x).

I mean, it seems like I do not have the actual instructions that came with this exercise.

If you follow the guidelines contained within the post titled, "Read Before Posting", you will get better help here.

 
ok, first of all, i am not so good at typing equation.

the question is
Graph the Function

f(x) = 2 - ln(x+4)
is there a way to show how to graph instead just put it in the graphic calculator?

cause in my class, my teacher want us to show all work or no credit.

schools these day, making it more complicated.
 
alyren said:
i am not so good at typing equation.

:idea: It is especially people who lack typing skills who should search out their typing mistakes and correct them. This process is called "proofreading".

the question is
Graph the Function

f(x) = 2 - ln(x+4)

is there a way to show how to graph instead just put it in the graphic calculator?

Yes, there are ways to do this.
Click to expand...

I do not know what you've learned, so far, or what your class expects on this exercise.

Without using a graphing calculator, there are at least two ways to graph function f.

(1) Make a table of values

(2) Start with the graph of ln(x) and apply transformations



If you want to make a table of values, you need to pick some values for x.

Therefore, begin by considering the domain of f.

Since the domain is x > -4, you need to pick values for x that are greater than -4 and calculate their corresponding y values.

Plot those points, and connect them with a smooth curve.



If you want to apply transformations, instead, then you first need to be familiar with the graph of the natural log function ln(x).

Adding 4 to x shifts the graph of ln(x) four units to the left.

Multiplying ln(x + 4) by -1 reflects the graph of ln(x + 4) across the x-axis.

Adding 2 to -ln(x + 4) shifts the graph of -ln(x + 4) up 2 units.

The result is the graph of 2 - ln(x + 4).

 
You must log in or register to reply here.
Top