Prove Existence Unique Real Solution

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SUMMARY

The discussion focuses on proving the existence of a unique real solution for the equation x³ + x² - 1 = 0 within the interval x = 2/3 and x = 1. The Intermediate Value Theorem confirms that a solution exists in this range, while the Mean Value Theorem establishes the uniqueness of this solution. The approximate solution of x = 0.75488 is acknowledged but not required for the proof. The key takeaway is the application of these theorems to validate the existence and uniqueness of the solution.

PREREQUISITES
  • Understanding of the Intermediate Value Theorem
  • Familiarity with the Mean Value Theorem
  • Basic knowledge of polynomial functions
  • Ability to analyze real-valued functions
NEXT STEPS
  • Study the proofs of the Intermediate Value Theorem
  • Explore the Mean Value Theorem and its applications
  • Learn about polynomial root-finding techniques
  • Investigate numerical methods for approximating solutions
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Mathematics students, educators, and anyone interested in real analysis or calculus, particularly those studying the properties of polynomial equations and their solutions.

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Homework Statement


Prove Existence Unique Real Solution to
## x^{3} + x^{2} -1 =0 ## between ## x= \frac{2}{3} \text{and} x=1##

The Attempt at a Solution



## x^{2} ( x+1) =1 ##
I know that the solution is x =0.75488, but this came from some website. How do I find this number without a calculator?
 
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You don't actually need to find the solution. You just need to know it exists. Think intermediate value theorem.
 
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The intermediate value theorem shows that there exist a solution betweem 2/3 and 1. The mean value theorem shows that there is only one.
 

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