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IB MYP 4-5 Maths-Transformation of quadratic functions- Study Notes

IB MYP 4-5 Maths- Transformation of quadratic functions- Study Notes - New Syllabus

IB MYP 4-5 Maths- Transformation of quadratic functions – Study Notes

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  • Transformation of quadratic functions

IB MYP 4-5 Maths- Transformation of quadratic functions – Study Notes – All topics

Transformation of Quadratic Functions

Transformation of Quadratic Functions

The basic quadratic function is:

\( y = x^2 \)

The general form after transformation is:

\( y = a(x – h)^2 + k \)

  • \( a \): Controls vertical stretch/compression and reflection.
  • \( h \): Controls horizontal shift (left/right).
  • \( k \): Controls vertical shift (up/down).

Types of Transformations and Their Effect on the Function:

  1. Vertical Shift:

    Change: \( y = f(x) + k \)

    Effect: Shift up by \( k \) if \( k > 0 \), down by \( |k| \) if \( k < 0 \).

  2. Horizontal Shift:

    Change: \( y = f(x – h) \)

    Effect: Shift right by \( h \) if \( h > 0 \), left by \( |h| \) if \( h < 0 \).

  3. Vertical Stretch/Compression:

    Change: \( y = a \cdot f(x) \)

    Effect: If \( |a| > 1 \), parabola is narrower (stretched). If \( 0 < |a| < 1 \), it is wider (compressed).

  4. Reflection in the x-axis:

    Change: \( y = -f(x) \)

    Effect: Flips the parabola upside down.

Vertex Form: \( y = a(x – h)^2 + k \)

Vertex: \( (h, k) \)

Axis of Symmetry: \( x = h \)

Example :

Describe the transformation of \( y = (x – 3)^2 + 2 \) from \( y = x^2 \).

▶️ Answer/Explanation

Compare with \( y = (x – h)^2 + k \):

  • \( h = 3 \) → Shift 3 units right.
  • \( k = 2 \) → Shift 2 units up.
  • No stretch or reflection (\( a = 1 \)).

New Vertex: (3, 2).

Example :

Describe the transformation of \( y = -2(x + 1)^2 – 4 \) from \( y = x^2 \).

▶️ Answer/Explanation

Compare with \( y = a(x – h)^2 + k \):

  • \( a = -2 \) → Vertical stretch by factor 2 and reflection in x-axis.
  • \( h = -1 \) → Shift 1 unit left.
  • \( k = -4 \) → Shift 4 units down.

New Vertex: (-1, -4).

Summary Table of Transformation

TransformationChange in FunctionEffect on Graph
Vertical Shift\( y = f(x) + k \)Shift up/down by \( k \)
Horizontal Shift\( y = f(x – h) \)Shift right/left by \( h \)
Stretch/Compression\( y = a f(x) \)Narrower (|a|>1) or wider (0<|a|<1)
Reflection\( y = -f(x) \)Flip across x-axis
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