Quick question about exponential and logarithms

In summary, the conversation discusses the simplification of ln(e^(-8.336/10c)). It is stated that this can be simplified to -8.336/10c, but the speaker is confused because their lecture notes simplify it to 1/(8.336/10c). The expert clarifies that the lecture notes are incorrect and that the correct simplification is -8.336/10c. The conversation also mentions the identity e^(-a) = 1/(e^a) and how it differs from e^(1/a).
  • #1
rlm42
2
0
If I have ln(e^(-8.336/10c)) wouldn't that be the same as ln(e^(1/(8.336/10c))) therefore = 1/(8.336/10c) = 10c/8.336? I am confused about this because in my lecture notes they simplified ln(e^(-8.336/10c)) to just = -8.336/10c :confused:

Your help would be appreciated!
 
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  • #2
Hey rlm42 and welcome to the foums.

If you let x = -8.336/10c and use the fact that e^(ln(x)) = ln(e^(x)) = x then it means that

ln(e^(x)) = x = ln(e^(-8.336/10c)) = -8.336/10c.

All I'm doing is replacing a complex variable with a simple variable and using the identities for logarithms and exponentials.
 
  • #3
nvm thnaks!
 
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  • #4
e^(-a) = 1/(e^a) not e^(1/a). There is a difference.
 

FAQ: Quick question about exponential and logarithms

1. What is the difference between exponential and logarithmic functions?

Exponential functions are equations in which the variable appears in the exponent, while logarithmic functions are equations in which the variable appears in the base. In other words, exponential functions represent growth or decay, while logarithmic functions represent the inverse of exponential growth or decay.

2. How do you solve exponential and logarithmic equations?

To solve an exponential equation, you must use logarithms. If the equation is in the form of b^x = y, take the logarithm of both sides with base b to cancel out the exponent and solve for x. To solve a logarithmic equation, you must use exponentials. If the equation is in the form of log base b of x = y, rewrite it as b^y = x and solve for x.

3. What are some real-world applications of exponential and logarithmic functions?

Exponential functions are used to model growth or decay in many fields such as population growth, compound interest, and radioactive decay. Logarithmic functions are used to represent data that grows exponentially, such as the Richter scale for earthquakes, pH scale for acidity, and decibel scale for sound intensity.

4. Can exponential and logarithmic functions be graphed?

Yes, both exponential and logarithmic functions can be graphed. Exponential functions have a characteristic shape of a curve that either increases or decreases rapidly, depending on the base. Logarithmic functions have a characteristic shape of a curve that starts off with a steep slope and then levels off as the input increases.

5. Are there any rules or properties for working with exponential and logarithmic functions?

Yes, there are a few rules and properties that can help simplify and manipulate exponential and logarithmic equations. These include the product rule, quotient rule, power rule, and change of base formula for logarithms. It is important to follow these rules when solving equations involving exponential and logarithmic functions.

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