Math Problem Statement

Use the vertex (h,k) and a point on the graph (x,y)

to find the standard form of the quadratic function.

(h,k)=(−3,−1) , (x,y)=(−4,1)

Solution

To find the standard form of the quadratic function using the vertex (h,k)=(3,1)(h, k) = (-3, -1) and a point on the graph (x,y)=(4,1)(x, y) = (-4, 1), we follow these steps:

Step 1: Use the vertex form of a quadratic function

The vertex form of a quadratic function is:

f(x)=a(xh)2+kf(x) = a(x - h)^2 + k

Where:

  • aa is a constant to be determined.
  • (h,k)(h, k) is the vertex of the parabola.

Substitute the given vertex (h,k)=(3,1)(h, k) = (-3, -1) into the vertex form:

f(x)=a(x+3)21f(x) = a(x + 3)^2 - 1

Step 2: Substitute the point (x,y)=(4,1)(x, y) = (-4, 1) into the equation

Now, use the point (x,y)=(4,1)(x, y) = (-4, 1) to find the value of aa. Substitute x=4x = -4 and y=1y = 1 into the equation:

1=a(4+3)211 = a(-4 + 3)^2 - 1

Simplify the equation:

1=a(1)211 = a(1)^2 - 1

1=a11 = a - 1

Step 3: Solve for aa

Add 1 to both sides:

2=a2 = a

Thus, a=2a = 2.

Step 4: Write the standard form

Now that we know a=2a = 2, substitute this value into the equation:

f(x)=2(x+3)21f(x) = 2(x + 3)^2 - 1

This is the vertex form of the quadratic function. To express this in standard form, we expand the equation:

f(x)=2(x2+6x+9)1f(x) = 2(x^2 + 6x + 9) - 1

f(x)=2x2+12x+181f(x) = 2x^2 + 12x + 18 - 1

f(x)=2x2+12x+17f(x) = 2x^2 + 12x + 17

Final Answer:

The standard form of the quadratic function is:

f(x)=2x2+12x+17f(x) = 2x^2 + 12x + 17


Would you like a more detailed explanation on any of the steps?

Here are 5 related questions for further practice:

  1. How do you convert a quadratic function from standard form to vertex form?
  2. How can you find the axis of symmetry of a quadratic function in standard form?
  3. What is the importance of the vertex in the graph of a quadratic function?
  4. How do you determine if a quadratic function opens upward or downward?
  5. How do you calculate the y-intercept of a quadratic function?

Tip: Always double-check your calculations when solving for aa using a point, as any small mistake can affect the entire equation.

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Math Problem Analysis

Mathematical Concepts

Algebra
Quadratic Functions
Vertex Form
Standard Form

Formulas

f(x) = a(x - h)^2 + k
Standard form: ax^2 + bx + c

Theorems

Vertex form of a quadratic function

Suitable Grade Level

Grades 9-11