Exponential equation vs Logarithmic

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    Exponential Logarithmic
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Discussion Overview

The discussion centers around the relationship between exponential functions of the form y=a^x and logarithmic functions y=loga(x). Participants explore various aspects including equations, graphs, and the properties of these functions as inverses of each other.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants note that logarithmic functions are the inverse of exponential functions, stating that if y=a^x, then x=loga(y).
  • There is a suggestion that the graph of the logarithmic function can be obtained by reflecting the graph of the exponential function across the line y=x.
  • Participants discuss the specific points of intersection for exponential functions, particularly that they intersect the y-axis at (0,1) for all a>0.
  • One participant emphasizes the importance of understanding the domains and ranges of both functions, indicating that the domain of the exponential function corresponds to the range of the logarithmic function and vice versa.
  • It is mentioned that the exponential function generally has a domain of all real numbers and a range of positive real numbers, while the logarithmic function has a domain of positive real numbers and a range of all real numbers.
  • There is a note that the bounds of the functions can affect the quadrants in which they are located, especially if transformations are applied.

Areas of Agreement / Disagreement

Participants generally agree on the inverse relationship between exponential and logarithmic functions and the reflection property of their graphs. However, there are varying levels of certainty regarding specific properties and graphical representations, indicating that some aspects remain unresolved.

Contextual Notes

Participants express uncertainty about certain conditions, such as the behavior of the functions at specific values (e.g., a=0) and the implications of transformations on the graphs.

navneet
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Hi I was wondering what is the relationship between y=a^x for exponential and y=loga (x) for log

I koe that we can divided this questiong further such as

a) equations --- which I am not sure

b) Graphs - I think we can say that the graph of the log equation is the reflection of exponential, and I stuck, also can we say something about which quads are they in??

please help me :confused:
 
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navneet said:
Hi I was wondering what is the relationship between y=a^x for exponential and y=loga (x) for log
I koe that we can divided this questiong further such as
a) equations --- which I am not sure
b) Graphs - I think we can say that the graph of the log equation is the reflection of exponential, and I stuck, also can we say something about which quads are they in??
please help me :confused:

[itex]log_a(x)[/itex] is simply the inverse funtion of [itex]a^x[/itex].

To get the graph of [itex]log_a(x)[/itex], simply draw the graph of [itex]a^x[/itex] and do a reflection on the y=x line.

http://www.themathpage.com/aPreCalc/logarithmic-exponential-functions.htm

Look there for graphs of both functions.

All exponential functions intersect the y-axis at y=1, so they all have the point (0,1). Make sure you have that in the graph. We know this is true because...

Let... f(x) = a^x

Then... f(0) = a^0 = 1, for all a>0. Not sure for a=0.

Anyways, read along that page and let us know if you have more questions.
 
As JasonRox said, ax and loga x are inverse functions. That is, if y= ax, then x= loga y.

The graph of any bijective function, reflected in the y= x line, is the graph of the inverse function.
 
JasonRox said:
...Let... f(x) = a^x
Then... f(0) = a^0 = 1, for all a>0. Not sure for a=0.
a0 = 1 [itex]\forall \ a \neq 0[/itex]... :approve:
 
VietDao29 said:
a0 = 1 [itex]\forall \ a \neq 0[/itex]... :approve:

You must write according to the audience.
 
Adding on to what JasonRox said, in order to accurately graph the functions the bounds (domains/ranges and restrictions) must also be known. Since exponential equations and logarithmic equations are inverse functions, that means that the domain for the exponential is the range for the logarithmic, and vice versa.

In general, for the exponential function, the domain D is generally { D | -inf < x < +inf } with the range being { R | 0 < y < +inf }. The logarithmic function, is the exact opposite. For logarithmic equations, the domain D is { D | 0 < x < +inf } and the range is {R | -inf < y < +inf }. The bounds of the function will determine what quadrant the function is in (unless the function is shifted over [y=a^(x) - 1] or multiplied by a negative, such as y=-a^x).
 

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