01 76 38 08 47
Kartable logo
HomeBrowseSearchLog in

To enjoy 10 free documents.

Kartable logo
HomeBrowseSearchLog in

To enjoy 10 free documents.

  1. Home
  2. 12th grade
  3. Precalculus
  4. Exercise : Calculate expressions involving greatest integer functions

Calculate expressions involving greatest integer functions Precalculus

Let f be the function defined as \lfloor x-\dfrac{3}{5} \rfloor. What is f\left( \dfrac{3}{7} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( \dfrac{3}{7} \right)=\lfloor \dfrac{3}{7}-\dfrac{3}{5} \rfloor=\lfloor -\dfrac{6}{35} \rfloor

Since -\dfrac{6}{35}\in\left[-1{,}0\right), we can conclude that:

f\left( \dfrac{3}{7} \right)=-1

Let f be the function defined as \lfloor x+\dfrac{1}{2} \rfloor. What is f\left( \dfrac{3}{4} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( \dfrac{3}{4} \right)=\lfloor\dfrac{3}{4}+\dfrac{1}{2} \rfloor=\lfloor \dfrac{5}{4} \rfloor

Since \dfrac{5}{4}\in\left[1{,}2\right), we can conclude that:

f\left( \dfrac{3}{4} \right)=1

Let f be the function defined as \lfloor 3x-\dfrac{1}{4} \rfloor. What is f\left( -\dfrac{1}{2} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( -\dfrac{1}{2} \right)=\lfloor 3\cdot\left( -\dfrac{1}{2} \right)-\dfrac{1}{4} \rfloor=\lfloor -\dfrac{7}{4} \rfloor

Since -\dfrac{7}{4}\in\left[-2,-1\right), we can conclude that:

f\left( -\dfrac{1}{2} \right)=-2

Let f be the function defined as \lfloor 5x+\dfrac{2}{3} \rfloor. What is f\left( -\dfrac{1}{3} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( -\dfrac{1}{3} \right)=\lfloor5\cdot\left( -\dfrac{1}{3} \right)+\dfrac{2}{3} \rfloor=\lfloor -1 \rfloor

Since -1\in\left[-1{,}0\right), we can conclude that:

f\left( -\dfrac{1}{3} \right)=-1

Let f be the function defined as \lfloor x-\dfrac{7}{5} \rfloor. What is f\left( \dfrac{3}{10} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( \dfrac{3}{10} \right)=\lfloor \dfrac{3}{10}-\dfrac{7}{5} \rfloor=\lfloor -\dfrac{11}{10} \rfloor

Since -\dfrac{11}{10}\in\left[-2,-1\right), we can conclude that:

f\left( \dfrac{3}{10} \right)=-2

Let f be the function defined as \lfloor x-\dfrac{2}{3} \rfloor . What is f\left( \dfrac{5}{6} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( \dfrac{5}{6} \right)=\lfloor \dfrac{5}{6}-\dfrac{2}{3} \rfloor=\lfloor \dfrac{1}{6} \rfloor

Since \dfrac{1}{6}\in\left[0{,}1\right), we can conclude that:

f\left( \dfrac{5}{6} \right)=0

Let f be the function defined as \lfloor-3x+\dfrac{1}{4} \rfloor . What is f\left( \dfrac{3}{8} \right) ?

The greatest integer function \lfloor a\rfloor determines the greatest integer less than or equal to a.

In our problem:

f\left( \dfrac{3}{8} \right)=\lfloor -3\left( \dfrac{3}{8}\right)+\dfrac{1}{4} \rfloor=\lfloor -\dfrac{9}{8}+\dfrac{1}{4} \rfloor=\lfloor -\dfrac{7}{8} \rfloor

Since -\dfrac{7}{8}\in\left[-1{,}0\right), we can conclude that:

f\left( \dfrac{3}{8} \right)=-1

The editorial charter guarantees the compliance of the content with the official National Education curricula. Learn more

The courses and exercises are written by the Kartable editorial team, made up of teachers certified and accredited. Learn more

See also
  • Course : Greatest integer function
  • Exercise : Solve equations involving greatest integer function with calculations
  • Exercise : Solve inequalities involving greatest integer function with calculations
  • support@kartable.com
  • Legal notice

© Kartable 2026