How to Isolate Implicit Equations Involving Logs, Sines, and More?

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Discussion Overview

The discussion revolves around the challenge of isolating implicit equations involving logarithmic and trigonometric functions, specifically focusing on the equation x^(3/2) = sin(x). Participants explore methods for finding exact solutions versus numerical approximations.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant expresses difficulty in isolating x in the equation x^(3/2) = sin(x) and seeks an exact solution.
  • Another participant suggests that the equation cannot be solved analytically and that numerical approximations are the best available method.
  • A different participant notes that there is no expectation of a "nice" solution to the equation, providing a numerical approximation to 500 decimal places.
  • One participant questions how the 500 decimal place answer was obtained.
  • Another participant mentions that software like Mathematica can compute such precise values.
  • A participant raises the point that x=0 could be considered an exact solution, prompting further inquiry.

Areas of Agreement / Disagreement

There is no consensus on whether an exact solution exists, with some participants asserting that numerical methods are the only viable approach while others suggest that x=0 may be an exact solution.

Contextual Notes

The discussion highlights the limitations of analytical solutions for certain equations and the reliance on numerical methods for high precision. The nature of implicit equations and the definitions of "exact" solutions are also points of contention.

Who May Find This Useful

Readers interested in mathematical problem-solving, numerical methods, and the challenges of isolating variables in complex equations may find this discussion relevant.

tom92373
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I was working on double integrals when I came across the equation: x^(3/2)=sin(x).
There was no noticeable way to isolate the equation for x without having a function of x equal to x. I am wondering how to isolate equations involving logs, sines, etc when it is given in an implicit form.
Using a computer, I was able to get an approximation of 0 and 8.02... How do I get the EXACT value of x?
 
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I don't think that can be solved analytically, numerical approximations are the best you can get.
 
There's no reason to expect a nice solution to that equation.

To 500 decimal places:
0.80280373173788931551183532460400044122266891061652741081013964565691641862577997739822547061430396268572323604994666281323668533410644604205801464291930503518478667486487218236513935782397374909479614327907963131119225878971201268489647029085385407187785694454923172056331593018083775727247023723969536341968998158469732909155080566871504200160137298683450160853972584968512566509877215100019308073835565249990882682850748486897243599882872536008937760137965323934876164878700580114920356083682742718
 
How did you get an answer to 500 decimal places?!
 
Mathematica (for example) can do it.
 
What's wrong with x=0 as an exact solution??
 

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