Math Problem Statement

State if the quadratic has a minimum or maximum. Find the equation for the Axis of Symmetry, Vertex, Domain and Range. Round to nearest hundredth if necessary.

(1)y=0.25 x²-2x+5 (2)y= x²+3x+1 (3) y=2x²+4x-2 (4)y= x²-2x+1

Solution

Let's analyze each quadratic equation to determine whether it has a minimum or maximum, find the Axis of Symmetry, Vertex, Domain, and Range.


General Form of a Quadratic Equation

The standard form is y=ax2+bx+cy = ax^2 + bx + c.

  • If a>0a > 0, the parabola opens upwards (has a minimum).
  • If a<0a < 0, the parabola opens downwards (has a maximum).
  • Axis of Symmetry: x=b2ax = -\frac{b}{2a}
  • Vertex: Substitute x=b2ax = -\frac{b}{2a} into the equation to find yy-coordinate.
  • Domain: For all quadratics, the domain is (,)(-\infty, \infty).
  • Range: Determined by the vertex and the parabola's direction.

(1) y=0.25x22x+5y = 0.25x^2 - 2x + 5

  • a=0.25>0a = 0.25 > 0: Parabola opens upwards → Minimum.
  • Axis of Symmetry: x=22(0.25)=4x = -\frac{-2}{2(0.25)} = 4
  • Vertex: y=0.25(4)22(4)+5=0.25(16)8+5=48+5=1y = 0.25(4)^2 - 2(4) + 5 = 0.25(16) - 8 + 5 = 4 - 8 + 5 = 1
    Vertex: (4,1)(4, 1).
  • Domain: (,)(-\infty, \infty)
  • Range: Since the minimum yy-value is 1 (from the vertex),
    Range: [1,)[1, \infty).

(2) y=x2+3x+1y = x^2 + 3x + 1

  • a=1>0a = 1 > 0: Parabola opens upwards → Minimum.
  • Axis of Symmetry: x=32(1)=1.5x = -\frac{3}{2(1)} = -1.5
  • Vertex: y=(1.5)2+3(1.5)+1=2.254.5+1=1.25y = (-1.5)^2 + 3(-1.5) + 1 = 2.25 - 4.5 + 1 = -1.25
    Vertex: (1.5,1.25)(-1.5, -1.25).
  • Domain: (,)(-\infty, \infty)
  • Range: Since the minimum yy-value is 1.25-1.25:
    Range: [1.25,)[-1.25, \infty).

(3) y=2x2+4x2y = 2x^2 + 4x - 2

  • a=2>0a = 2 > 0: Parabola opens upwards → Minimum.
  • Axis of Symmetry: x=42(2)=1x = -\frac{4}{2(2)} = -1
  • Vertex: y=2(1)2+4(1)2=2(1)42=4y = 2(-1)^2 + 4(-1) - 2 = 2(1) - 4 - 2 = -4
    Vertex: (1,4)(-1, -4).
  • Domain: (,)(-\infty, \infty)
  • Range: Since the minimum yy-value is 4-4:
    Range: [4,)[-4, \infty).

(4) y=x22x+1y = x^2 - 2x + 1

  • a=1>0a = 1 > 0: Parabola opens upwards → Minimum.
  • Axis of Symmetry: x=22(1)=1x = -\frac{-2}{2(1)} = 1
  • Vertex: y=(1)22(1)+1=12+1=0y = (1)^2 - 2(1) + 1 = 1 - 2 + 1 = 0
    Vertex: (1,0)(1, 0).
  • Domain: (,)(-\infty, \infty)
  • Range: Since the minimum yy-value is 00:
    Range: [0,)[0, \infty).

Final Results in Tabular Form

EquationMin/MaxAxis of SymmetryVertexDomainRange
y=0.25x22x+5y = 0.25x^2 - 2x + 5Minimumx=4x = 4(4,1)(4, 1)(,)(-\infty, \infty)[1,)[1, \infty)
y=x2+3x+1y = x^2 + 3x + 1Minimumx=1.5x = -1.5(1.5,1.25)(-1.5, -1.25)(,)(-\infty, \infty)[1.25,)[-1.25, \infty)
y=2x2+4x2y = 2x^2 + 4x - 2Minimumx=1x = -1(1,4)(-1, -4)(,)(-\infty, \infty)[4,)[-4, \infty)
y=x22x+1y = x^2 - 2x + 1Minimumx=1x = 1(1,0)(1, 0)(,)(-\infty, \infty)[0,)[0, \infty)

Would you like detailed steps for any specific equation?
Here are 5 related questions to extend your understanding:

  1. How do we determine if a parabola has a minimum or maximum without graphing?
  2. Can you find the x-intercepts (roots) for any of these equations?
  3. What would the graph of each parabola look like?
  4. How does the coefficient aa influence the steepness of the parabola?
  5. How do you calculate the range when the parabola opens downward?

Tip: Always check the sign of aa in y=ax2+bx+cy = ax^2 + bx + c to determine the parabola's direction and vertex type!

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Equations
Parabolas
Vertex Form
Domain and Range

Formulas

Axis of Symmetry: x = -b / 2a
Vertex Calculation: Substitute x = -b / 2a into y = ax^2 + bx + c
General form of Quadratic Equation: y = ax^2 + bx + c

Theorems

Properties of Quadratic Functions

Suitable Grade Level

Grades 8-10