Q. Which is the graph of \(f(x) = x^2 – 2x + 3\)?
Answer
Complete the square:/strong
\[ f(x) = x^2 – 2x + 3 = (x^2 – 2x + 1) + 2 = (x – 1)^2 + 2. \]
Therefore the graph is a parabola opening upward with vertex at \( (1,\,2) \), axis of symmetry \( x = 1 \), y-intercept \( f(0) = 3 \), and no x-intercepts since the minimum value is \(2\).
Detailed Explanation
Problem: Analyze the quadratic function \( f(x)=x^{2}-2x+3 \)
Step 1 – Identify the coefficients
The function is in standard form \( f(x)=ax^{2}+bx+c \). Here
\[
a=1,\qquad b=-2,\qquad c=3.
\]
Step 2 – Determine the direction of the parabola
Since the leading coefficient \( a=1 \) is positive, the parabola opens upward.
Step 3 – Find the vertex
The \(x\)-coordinate of the vertex is given by
\[
x=-\dfrac{b}{2a}=-\dfrac{-2}{2(1)}=\dfrac{2}{2}=1.
\]
Evaluate \(f\) at \(x=1\) to get the \(y\)-coordinate:
\[
f(1)=1^{2}-2(1)+3=1-2+3=2.
\]
Thus the vertex is at \( (1,2) \).
Step 4 – Find the y-intercept
Set \(x=0\):
\[
f(0)=0^{2}-2\cdot 0+3=3.
\]
The \(y\)-intercept is \( (0,3) \).
Step 5 – Check for x-intercepts
Compute the discriminant \(D=b^{2}-4ac\):
\[
D=(-2)^{2}-4(1)(3)=4-12=-8.
\]
Because the discriminant is negative, there are no real \(x\)-intercepts; the graph does not cross the \(x\)-axis.
Step 6 – Describe the graph
The graph is an upward-opening parabola with its minimum (vertex) at \( (1,2) \). It crosses the \(y\)-axis at \( (0,3) \) and lies entirely above the \(x\)-axis (no real roots).
Graph
FAQs
What kind of graph is (f(x)=x^2-2x+3)?
What is the vertex?
What is the axis of symmetry?
Does the parabola have x-intercepts (real roots)?
What is the y-intercept?
What are the domain and range?
How can I sketch it quickly?
How is (f(x)) related to (y=x^2)?
What is the minimum value of (f(x))?
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