Math Problem Statement

Sketch the graph of y = x^2 + 2x + 3

Solution

To sketch the graph of y=x2+2x+3y = x^2 + 2x + 3, let’s analyze the quadratic equation step-by-step:


1. Identify the general form of the quadratic equation

The equation y=x2+2x+3y = x^2 + 2x + 3 is in standard form:
y=ax2+bx+cy = ax^2 + bx + c Here:

  • a=1a = 1 (coefficient of x2x^2)
  • b=2b = 2 (coefficient of xx)
  • c=3c = 3 (constant term).

Since a>0a > 0, the parabola opens upward.


2. Find the vertex of the parabola

The vertex (h,k)(h, k) of a parabola in standard form can be found using:
x=b2ax = -\frac{b}{2a} Substitute a=1a = 1 and b=2b = 2:
x=22(1)=1x = -\frac{2}{2(1)} = -1

To find the yy-coordinate of the vertex, substitute x=1x = -1 into the equation:
y=(1)2+2(1)+3y = (-1)^2 + 2(-1) + 3 y=12+3=2y = 1 - 2 + 3 = 2 Thus, the vertex is at (1,2)(-1, 2).


3. Find the y-intercept

The y-intercept occurs when x=0x = 0:
y=02+2(0)+3=3y = 0^2 + 2(0) + 3 = 3 Thus, the y-intercept is (0,3)(0, 3).


4. Determine the axis of symmetry

The axis of symmetry is the vertical line that passes through the vertex. Its equation is:
x=1x = -1


5. Identify additional points

To get more points for the graph, substitute nearby xx-values:

  • For x=2x = -2:
    y=(2)2+2(2)+3=44+3=3(point: (-2, 3)).y = (-2)^2 + 2(-2) + 3 = 4 - 4 + 3 = 3 \quad \text{(point: (-2, 3))}.

  • For x=1x = 1:
    y=(1)2+2(1)+3=1+2+3=6(point: (1, 6)).y = (1)^2 + 2(1) + 3 = 1 + 2 + 3 = 6 \quad \text{(point: (1, 6))}.


6. Sketch the graph

  • The parabola opens upward.
  • The vertex is at (1,2)(-1, 2).
  • The y-intercept is (0,3)(0, 3).
  • Symmetry helps reflect points across x=1x = -1 to complete the graph.

Would you like me to plot this graph visually for you? Let me know! 😊


Related Questions:

  1. How do you find the roots of a quadratic equation?
  2. What happens to the graph if the coefficient aa changes?
  3. How is the vertex form of a quadratic equation derived?
  4. What are real-life applications of parabolas?
  5. How do you determine if a quadratic has real or complex roots?

Tip: A quadratic graph is symmetric around its vertex—use this property to save time when sketching!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Graphing Parabolas

Formulas

Standard form of a quadratic equation: y = ax^2 + bx + c
Vertex formula: x = -b / 2a
Equation of axis of symmetry: x = h

Theorems

The graph of a quadratic function is a parabola.

Suitable Grade Level

Grades 8-10