Study the continuity of this function

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SUMMARY

The function f(x) = [x^2]sin(πx), where [x] denotes the integer part of x, is not continuous across all real numbers. While sin(πx) is continuous, the integer part function [x^2] introduces discontinuities at integer values of x^2. Therefore, the product of these two functions results in a function that is continuous only at points where x^2 is not an integer, confirming that the initial assumption of trivial continuity is incorrect.

PREREQUISITES
  • Understanding of continuity in real-valued functions
  • Familiarity with the integer part function, also known as the floor function
  • Knowledge of trigonometric functions, specifically sine
  • Basic calculus concepts, particularly limits and continuity
NEXT STEPS
  • Study the properties of the floor function and its impact on continuity
  • Learn about piecewise functions and their continuity conditions
  • Explore the concept of limits in relation to discontinuities
  • Investigate the behavior of products of continuous and discontinuous functions
USEFUL FOR

Students in calculus or analysis courses, mathematics educators, and anyone studying the properties of continuous functions and their applications.

Felafel
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Homework Statement



f(x) = [x^2]sinπx, x ∈ R, being [x] the integer part of x


Homework Equations





The Attempt at a Solution



I'd say it's trivially continuos on all R, because it's the product of two continuos functions: y: = [x^2] and g: = sinπx.
However, being part of my analysis class homework (always a bit tricky to solve), it seems a bit too easy to me. So, i thought there might be something strange I haven't noticed. Or is my reasoning just correct?
thanks in advance!
 
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Felafel said:

Homework Statement



f(x) = [x^2]sinπx, x ∈ R, being [x] the integer part of x


Homework Equations





The Attempt at a Solution



I'd say it's trivially continuos on all R, because it's the product of two continuos functions: y: = [x^2] and g: = sinπx.
However, being part of my analysis class homework (always a bit tricky to solve), it seems a bit too easy to me. So, i thought there might be something strange I haven't noticed. Or is my reasoning just correct?
thanks in advance!

x^2 is continuous. The integer part of x^2 is not continuous.
 

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