Sigma Percentile
JEE Advanced 1978
LEVELJEE Main

Animated Solution for Mathematics - Functions: Draw the graph of for .

Visualized Solution

Introduction to

  • Function:
  • Given Domain:
  • We need to plot this on the Cartesian plane.

The Origin Point

  • Let's check the value at .
  • The graph passes through the origin .

Breaking Down the Modulus

  • The function contains a modulus:
  • Definition of modulus:
  • if
  • if

Case 1: Positive

  • Case 1: (Right side of -axis)
  • In this region,
  • Substitute into the function:

Graphing Case 1

  • This is the upper half of a rightward opening parabola.
  • At , .

Case 2: Negative

  • Case 2: (Left side of -axis)
  • In this region,
  • Substitute into the function:

Graphing Case 2

  • Since is negative, is positive, making the square root real.
  • At , .

Symmetry Analysis

  • Let's verify the symmetry mathematically.
  • Replace with :
  • Since , we get:

Conclusion: Even Function

  • Because , the function is an Even Function.
  • Even functions are always symmetric about the -axis.
  • The graph consists of two symmetric parabolic arcs meeting at the origin.

The Sigma Insight: Classification of Functions

Solution Diagram

Analyzing the Setup

Imagine you are standing on the Cartesian plane, ready to map out a function that seems simple but hides a beautiful geometric secret. We are tasked with graphing within the domain .
This is not just a line; it is a journey into the heart of symmetry and piecewise behavior.

The Anchor Point

The Origin
Every great journey starts with a single step, and for this function, that step is the origin. When we test , the math becomes incredibly elegant:
This confirms that our graph is anchored firmly at the point . This point acts as the pivot for our entire construction.

The Modulus Split

Breaking the Barrier
The modulus function is the gatekeeper of this problem. It forces us to split our world into two distinct realities.
By definition, when , and when . We cannot treat this as one monolithic equation; we must respect the boundary at the y-axis.

The Right Wing

The Parabolic Ascent
For the region where , our function simplifies beautifully to , or . If you have spent time with conic sections, you will recognize this instantly.
It is the upper half of a parabola that opens to the right. As moves from to , climbs from to . It is a smooth, accelerating curve that defines the right side of our graph.

The Left Wing

The Mirror Image
Now, we cross the y-axis into the territory where . Here, the modulus demands that . Our function becomes , or .
Do not be alarmed by the negative sign! Since is negative, is positive, keeping our output firmly in the realm of real numbers. At , we find:
This creates a mirror image of our right-wing parabola, opening to the left.

The Symmetry of the Even Function

When we step back and look at the two arcs meeting at the origin, we see a perfect balance. Mathematically, we have proven this is an Even Function because .
This symmetry is not just a visual treat; it is a fundamental property that makes the graph a mirror image across the y-axis. You have successfully navigated the piecewise definition, visualized the parabolic arcs, and understood the symmetry.
You have not just drawn a graph; you have understood the soul of the function.

Similar Questions

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