How do I solve the equation e^(x+3) = pi^x?

  • Context: Undergrad 
  • Thread starter Thread starter jaypee
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Discussion Overview

The discussion revolves around solving the equation e^(x+3) = pi^x, focusing on the methods and steps involved in manipulating the equation using logarithms. Participants explore various approaches to isolate x and express it in terms of logarithmic functions.

Discussion Character

  • Mathematical reasoning

Main Points Raised

  • One participant presents an initial attempt to solve the equation, expressing uncertainty about the correctness of their steps and notation.
  • Another participant corrects the notation used for logarithms, emphasizing that ln is a function and should be applied to an argument.
  • A third participant provides a clearer step-by-step solution, starting from taking the natural logarithm of both sides and isolating x, ultimately arriving at x = 3 / (ln(pi) - 1).
  • A separate post introduces a different equation, e^x = 4 - x^2, and seeks assistance, indicating a shift in focus from the original equation.

Areas of Agreement / Disagreement

There is no consensus on the initial approach to solving the equation, as participants express differing levels of clarity and correctness in their methods. The discussion remains unresolved regarding the initial participant's solution.

Contextual Notes

Some participants highlight issues with notation and the proper application of logarithmic functions, indicating potential misunderstandings in the manipulation of the equation.

jaypee
I'm having a hard time solving this:
e^(x+3) = pi^x


I got these results, but I'm not sure if it is correct:
ln^(x+3) = ln(pi^x)
(x+3)ln = xln(pi)
xln + 3ln = xln(pi)
3ln = xln(pi)-xln
3ln = x(ln(pi) - ln)

x = 3ln/ln(pi)-ln

NOTE: PI =3.14 (I don't know how to insert the symbol pi)
 
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That's the right way to go about, but remember, ln is a function... you have to write ln(something), ln by itself is not a number.

ln(e)=1

and you should be able to get it from there...
 
Yeah, you're kinda butchering things with your "ln raised to a power" and "ln by itself" stuff.

Step 1. Take the natural logarithm of both sides of the equation:

ln(e^(x+3)) = ln(pi^x)

this becomes

x+3 = x * ln(pi)

Step 2. Isolate x on one side of the equation

3 = x * ln(pi) - x
3 = x (ln(pi) - 1)

Step 3. Solve for x

x = 3 / (ln(pi) - 1)

- Warren
 
I'm having difficulty in solving for x,in the equation e^x=4-x^2
help please
lne^x=ln(4-x^2)
x=ln(4-x^2) and this is as far as iI got
 
Last edited:

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