Math Problem Statement

if[x Greatest integer less than or equal to x and (x)=x-[x]. How many real values of x satisfy the equation

Pick ONE option

2

0

More than 2

Solution

The problem describes two mathematical functions:

  1. xx: The greatest integer less than or equal to xx, also called the floor function.
  2. (x)=x(x) = x - x$$$$, which represents the fractional part of xx, denoted as {x}\{x\}. This gives the decimal part of xx, meaning 0{x}<10 \leq \{x\} < 1.

Now, the equation in question can be understood as:

[ [x] = x - [x] ]

Simplifying this equation:

[ [x] + [x] = x ]

2[x]=x2[x] = x

x=2[x]x = 2[x]

Since [x][x] is the greatest integer less than or equal to xx, this equation implies that xx is equal to twice an integer, meaning:

x=2nfor some integern.x = 2n \quad \text{for some integer} \, n.

However, we must also check that the fractional part of xx satisfies {x}=0\{x\} = 0. Since x=2nx = 2n, {x}=x[x]=2nn=0\{x\} = x - [x] = 2n - n = 0.

Thus, xx must be an integer, and specifically even integers.

Conclusion:

The values of xx are exactly even integers. Since there are infinitely many such integers, there are more than 2 real values that satisfy the equation.

The correct answer is: More than 2.


Do you want any further details or have any questions? Here are some related questions to think about:

  1. What are the properties of the floor function?
  2. How does the fractional part function behave for non-integer values?
  3. Can {x}\{x\} ever be negative?
  4. What would happen if the equation had been 3[x]=x3[x] = x instead of 2[x]=x2[x] = x?
  5. What is the geometric interpretation of the solution to this equation?

Tip: The fractional part function {x}\{x\} is always between 0 (inclusive) and 1 (exclusive).

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Math Problem Analysis

Mathematical Concepts

Algebra
Floor Function
Fractional Part Function
Equations

Formulas

Floor function: [x] = greatest integer less than or equal to x
Fractional part: {x} = x - [x]
Simplified equation: 2[x] = x

Theorems

Properties of the Floor Function
Properties of the Fractional Part Function

Suitable Grade Level

Grades 10-12