Step-by-Step Solution
Step 1: Identify Parameters and Vertex
For f(x)=ax2+bx+c:
a=1,b=−4,c=4
Since a=1>0, the parabola opens upwards, so the vertex is an absolute minimum point.
Recognizing the perfect square trinomial:
f(x)=(x−2)2
The vertex is immediately identified at (2,0).
Step 2: Intercepts & Tangency to Axis
- y-intercept: f(0)=(0−2)2=4⟹(0,4).
- x-intercept: (x−2)2=0⟹x=2 (a repeated real root). The parabola is tangent to the x-axis at the vertex (2,0) and never crosses below it.
- Axis of Symmetry:
x=2
Step 3: Domain and Range
- Domain: Defined everywhere on R:
Domain=R=(−∞,∞)
- Range: Because (x−2)2≥0 for all real numbers x:
Range=[0,∞)