Math Problem Statement

if x + 1/x = squareroot of 71, what is the value of x^2 + 1/x^2

Solution

We are given:

x+1x=71x + \frac{1}{x} = \sqrt{71}

We need to find the value of x2+1x2x^2 + \frac{1}{x^2}.

Step-by-Step Process:

  1. Square both sides of the equation to relate x2+1x2x^2 + \frac{1}{x^2} to x+1xx + \frac{1}{x}.

    Squaring x+1xx + \frac{1}{x}:

    (x+1x)2=x2+2+1x2\left( x + \frac{1}{x} \right)^2 = x^2 + 2 + \frac{1}{x^2}

    Therefore:

    x2+1x2+2=(71)2x^2 + \frac{1}{x^2} + 2 = \left( \sqrt{71} \right)^2

  2. Simplify the equation:

    x2+1x2+2=71x^2 + \frac{1}{x^2} + 2 = 71

    Subtract 2 from both sides:

    x2+1x2=712x^2 + \frac{1}{x^2} = 71 - 2

    x2+1x2=69x^2 + \frac{1}{x^2} = 69

Thus, the value of x2+1x2x^2 + \frac{1}{x^2} is 69\boxed{69}.

Would you like more details or have any questions?


Here are 5 related questions for deeper understanding:

  1. If x+1x=5x + \frac{1}{x} = 5, what is x2+1x2x^2 + \frac{1}{x^2}?
  2. If x+1x=10x + \frac{1}{x} = 10, what is the value of x2+1x2x^2 + \frac{1}{x^2}?
  3. How would you solve x2+1x2=45x^2 + \frac{1}{x^2} = 45 for x+1xx + \frac{1}{x}?
  4. Can you express x3+1x3x^3 + \frac{1}{x^3} in terms of x+1xx + \frac{1}{x}?
  5. What would happen if x+1x=0x + \frac{1}{x} = 0? What is x2+1x2x^2 + \frac{1}{x^2}?

Tip: Always remember that squaring both sides of an equation can introduce extraneous solutions, so it's good to verify the solutions afterward if possible.

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Math Problem Analysis

Mathematical Concepts

Algebra
Squaring Binomials
Simplification

Formulas

(x + 1/x)^2 = x^2 + 2 + 1/x^2
x^2 + 1/x^2 = (x + 1/x)^2 - 2

Theorems

Basic Algebraic Identities

Suitable Grade Level

Grades 9-11