IB MYP 4-5 Maths- Transformation of quadratic functions- Study Notes - New Syllabus
IB MYP 4-5 Maths- Transformation of quadratic functions – Study Notes
Extended
- 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:
- Vertical Shift:
Change: \( y = f(x) + k \)
Effect: Shift up by \( k \) if \( k > 0 \), down by \( |k| \) if \( k < 0 \).
- Horizontal Shift:
Change: \( y = f(x – h) \)
Effect: Shift right by \( h \) if \( h > 0 \), left by \( |h| \) if \( h < 0 \).
- 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).
- 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
Transformation | Change in Function | Effect 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 |