Sunday, January 27, 2013

3-2: Exponential and Logarithmic Functions (AKA Bloggerithms)

While in the land of Exponential Functions, you probably realized the stimulating graphs you created were, fascinatingly enough, one-to-one. Astounded by the implications of such a thing you probably also began to marvel at the possibilities of there existing an inverse - some might call it an evil twin - to your slope-ed friend.


Lucky for us, although intimidatingly rapid at first, our villain slows quickly. Rather than increasing its increase-tion with each increase in x and decreasing its decrease-tion with each decrease in x, this fiend would decrease its increase-tion with each increase and increase its decrease-tion with each decrease. (For a less word-ed analysis of this, see "Possibly Dangerous" on the right)

In sneaking a look at the next chapter in your book, you also probably discovered that this anti-exponent-graph is called the Logarithmic Function.

Logarithmic Function:
Although most commonly written in Logarithmic Form (top), the Logarithmic Function may also disguise itself as its counterpart in Exponential Form (bottom).
Both equations are asking what power you must raise a to in order to equal x. Stay informed. Do not become prey to its deception.

Log Graph:
Because the Logarithmic Function is the inverse of the Exponential Function, its domain, range, and asymptotes are switched. Shifting the graph up/down will change the intercept and right/left will change the asymptote and the domain.
   Domain: (0,∞)
Nautilus Shell- the perfect logarithmic spiral
   Range: (-∞,∞)
   Vertical Asymptote: x = 0
   Intercept: (1,0)

Log Properties:
    
    
Inverse Properties:
    
    
One -to- One Property:
    

The Natural Log: e
Just as it exists with exponents, the irrational number e also comes into play with logarithms.
It follows the same rules as any other logarithm but it is often written .
Log Doodles:  http://www.youtube.com/watch?v=ahXIMUkSXX0
Thats just about all there is to say about Logarithms until next section..
'Log'ing off.... Olivia Miller

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