Solving a Logarithm: Can't Remember How? Try Here!

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The equation x = b/D + a*log(D) presents a challenge for solving D due to its dual role as both a logarithmic input and a factor. It is suggested that solving for D in terms of elementary functions is not feasible. The Lambert W function may provide a solution, but it is not straightforward. Additionally, a Taylor Series expansion is proposed as a potential method for approximation. Ultimately, the consensus is that solving for D is complex and may require advanced mathematical techniques.
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Can't remember how to do this (trying to solve for D):

x = b/D + a*log(D)

Any takers? Or is this impossible?
 
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Additive inverse of b/D;
Multiplicative inverse of 'a';

Not sure if the rest is impossible. I'm stuck, since D is the input of the logarithm function and it occurs as a factor too. Am I forgetting something simple, or is this beyond "intermediate" level algebra?
 
symbolipoint said:
Additive inverse of b/D;
Multiplicative inverse of 'a';

Not sure if the rest is impossible. I'm stuck, since D is the input of the logarithm function and it occurs as a factor too. Am I forgetting something simple, or is this beyond "intermediate" level algebra?


Maybe I can simplify the problem here:

a, b, and c are real numbers, D is greater than zero

c = b/D + a*log(D)

how does one solve for D?
 
One doesn't. Not in terms of elementary functions anyway. It might be possible to solve it in terms of the "Lambert W function".
 
HallsofIvy said:
One doesn't. Not in terms of elementary functions anyway. It might be possible to solve it in terms of the "Lambert W function".

How bout a Taylor Series expansion?
 
Here is a little puzzle from the book 100 Geometric Games by Pierre Berloquin. The side of a small square is one meter long and the side of a larger square one and a half meters long. One vertex of the large square is at the center of the small square. The side of the large square cuts two sides of the small square into one- third parts and two-thirds parts. What is the area where the squares overlap?

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