Examples with solutions for Zeros of a Fuction: Finding a stationary point

Exercise #1

The following function has been graphed below:

f(x)=x2+5x+6 f(x)=-x^2+5x+6

Calculate points A and B.

BBBAAACCC

Video Solution

Step-by-Step Solution

To solve for the x-intercepts of the function f(x)=x2+5x+6 f(x) = -x^2 + 5x + 6 , we will find the roots of the quadratic equation x2+5x+6=0 -x^2 + 5x + 6 = 0 .

Let's attempt to factor this quadratic equation first. Rewrite the equation as follows:

x2+5x+6=0 -x^2 + 5x + 6 = 0 .

To factor, we look for two numbers that multiply to 6-6 (the product of aa and cc, where a=1a = -1 and c=6c = 6) and add to 55 (the middle coefficient bb).

The numbers that satisfy this condition are 1-1 and 66.

Thus, the quadratic can be factored as:

(x6)(x+1)=0(x - 6)(x + 1) = 0.

Setting each factor equal to zero gives us:

x6=0x - 6 = 0 or x+1=0x + 1 = 0.

Solving these equations, we find:

x=6x = 6 and x=1x = -1.

Thus, the points A and B, the x-intercepts of the function, are:

(1,0)(-1, 0) and (6,0) (6, 0).

Therefore, the solution to the problem is (1,0),(6,0)(-1, 0), (6, 0).

Answer

(1,0),(6,0) (-1,0),(6,0)

Exercise #2

The following function has been graphed below:

f(x)=x26x+5 f(x)=x^2-6x+5

Calculate points A and B.

AAABBB

Video Solution

Step-by-Step Solution

To solve for the points A and B, we need to find the roots of the function f(x)=x26x+5 f(x) = x^2 - 6x + 5 where f(x)=0 f(x) = 0 .

Let's proceed step-by-step:

  • Step 1: Set the function to zero
    We begin by setting the equation to zero: x26x+5=0 x^2 - 6x + 5 = 0 .
  • Step 2: Factor the quadratic
    We need to factor the expression. We look for two numbers that multiply to c=5 c = 5 and add to b=6 b = -6 . These numbers are 1-1 and 5-5.
  • Step 3: Write the factorization
    Therefore, we can write the quadratic as: (x1)(x5)=0(x - 1)(x - 5) = 0.
  • Step 4: Solve for the roots
    Set each factor equal to zero: \begin{align*} x - 1 &= 0 \\ x &= 1 \end{align*} \begin{align*} x - 5 &= 0 \\ x &= 5 \end{align*} The roots are x=1 x = 1 and x=5 x = 5 .
  • Step 5: Identify the Points A and B
    The points A and B, where the function intersects the x-axis, are (1,0)(1, 0) and (5,0)(5, 0).

Thus, the coordinates of points A and B are (1,0),(5,0) (1,0),(5,0) , which matches choice 1.

Answer

(1,0),(5,0) (1,0),(5,0)

Exercise #3

The following function has been graphed below:

f(x)=x28x+16 f(x)=x^2-8x+16

Calculate point A.

AAACCC

Video Solution

Step-by-Step Solution

Let's solve the problem by following the outlined analysis:

  • Step 1: Identify important points on the parabola.
  • Step 2: Calculate the y-intercept by evaluating f(0) f(0) .
  • Step 3: Confirm understanding of the vertex form and its characteristics.

Step 1: Identify the significant points on the function.
The function given is f(x)=x28x+16 f(x) = x^2 - 8x + 16 .

This function can be seen as
f(x)=(x4)2 f(x) = (x - 4)^2 .

This format not only indicates it is always non-negative but also reveals the vertex is located at x=4 x = 4 , importantly, with f(x)=0 f(x) = 0 .

Step 2: Calculate the y-intercept.
Evaluate the function at x=0 x = 0 :

f(0)=0280+16=16 f(0) = 0^2 - 8 \cdot 0 + 16 = 16 .
So, the y-intercept is (0,16) (0, 16) .

Thus, point A, which is often labeled at a crucial intercept, corresponds to the y-intercept of the function. The calculation confirms that point A is (0,16) (0, 16) .

Therefore, the solution to the problem is (0,16) (0,16) .

Answer

(0,16) (0,16)

Exercise #4

The following function has been plotted on the graph below:

f(x)=x28x+16 f(x)=x^2-8x+16

Calculate point C.

CCC

Video Solution

Step-by-Step Solution

To solve the exercise, first note that point C lies on the X-axis.

Therefore, to find it, we need to understand what is the X value when Y equals 0.

 

Let's set the equation equal to 0:

0=x²-8x+16

We'll use the preferred method (trinomial or quadratic formula) to find the X values, and we'll discover that

X=4

 

Answer

(4,0) (4,0)

Exercise #5

The following function has been graphed below:

f(x)=x23x4 f(x)=x^2-3x-4

Calculate points A and B.

CCCAAABBB

Video Solution

Step-by-Step Solution

To solve for points A and B, we find the x-intercepts of the function by setting:

f(x)=x23x4=0 f(x) = x^2 - 3x - 4 = 0

We check if it can be factored:

Factor x23x4 x^2 - 3x - 4 . The factors of -4 that add to -3 are -4 and 1.

Thus, factor the function as (x4)(x+1)=0 (x - 4)(x + 1) = 0 .

Set each factor to zero:

  • x4=0 x - 4 = 0 implies x=4 x = 4
  • x+1=0 x + 1 = 0 implies x=1 x = -1

These are the x-intercepts, or roots, of the quadratic function.

Therefore, the coordinates of points A and B, where the function intersects the x-axis, are A(1,0) A(-1, 0) and B(4,0) B(4, 0) .

The correct choice corresponding to these points is option 3: A(1,0),B(4,0) A(-1,0), B(4,0) .

Thus, the solution to the problem is A(1,0),B(4,0) A(-1,0), B(4,0) .

Answer

A(1,0),B(4,0) A(-1,0),B(4,0)

Exercise #6

The following function has been graphed below:

f(x)=x26x f(x)=x^2-6x

Calculate points A and B.

AAABBB

Video Solution

Step-by-Step Solution

To solve for the points A and B, where the graph of f(x)=x26x f(x) = x^2 - 6x intersects the x-axis, let's solve the equation f(x)=0 f(x) = 0 :
1. Write the equation in standard form:
x26x=0 x^2 - 6x = 0 .

2. Factor the quadratic equation:
x(x6)=0 x(x - 6) = 0 .

3. Set each factor equal to zero:
x=0 x = 0 or x6=0 x - 6 = 0 .

4. Solve each equation for x x :
x=0 x = 0 and x=6 x = 6 .

Thus, the points where the function intersects the x-axis, also the points A and B, are (0,0) (0,0) and (6,0) (6,0) .

Therefore, the solution to the problem is (6,0),(0,0) (6,0), (0,0) .

Answer

(6,0),(0,0) (6,0),\lparen0,0)

Exercise #7

The following function has been graphed below:

f(x)=x26x+8 f(x)=x^2-6x+8

Calculate points A and B.

AAABBB

Video Solution

Step-by-Step Solution

To solve the problem of finding points A and B on the graph of the function f(x)=x26x+8 f(x) = x^2 - 6x + 8 , we need to determine where this quadratic function equals zero.

Step-by-step Approach:

  • Step 1: Check Factoring Possibility
    The quadratic function is given by:
f(x)=x26x+8 f(x) = x^2 - 6x + 8

We will attempt to factor this quadratic expression. We are looking for two numbers that multiply to the constant term, 8, and add to the coefficient of x x , which is 6-6.

  • Step 2: Identify Factors
    The numbers 4 4 and 2 2 multiply to 8 8 and add to 6-6, if we consider their negative counterparts, 4-4 and 2-2:
(x4)(x2)=x26x+8 (x - 4)(x - 2) = x^2 - 6x + 8

This matches our expression, confirming that it is the correct factorization.

  • Step 3: Solve for Roots
    Set each factor equal to zero:
x4=0x=4 x - 4 = 0 \quad \Rightarrow \quad x = 4 x2=0x=2 x - 2 = 0 \quad \Rightarrow \quad x = 2

Thus, the points where the function intersects the x-axis, which are the roots, are (2,0) (2,0) and (4,0) (4,0) .

Therefore, the solution to the problem is that points A and B are at (2,0)(2,0) and (4,0)(4,0).

Final Solution:
The points A and B are (2,0)(2,0) and (4,0)(4,0).

Answer

(2,0),(4,0) (2,0),(4,0)

Exercise #8

The following function has been graphed below:

f(x)=x26x+5 f(x)=x^2-6x+5

Calculate point C.

AAABBBCCC

Video Solution

Step-by-Step Solution

We are required to find a particular point C on the graph of the function f(x)=x26x+5 f(x) = x^2 - 6x + 5 . Typically, important features of the graph include the vertex or y-intercept.

The function f(x)=x26x+5 f(x) = x^2 - 6x + 5 is a quadratic function in standard form, where a=1 a = 1 , b=6 b = -6 , and c=5 c = 5 . Since point C is labeled near the y-axis, it is likely related to the y-intercept. The y-intercept is found by evaluating the function at x=0 x = 0 .

Calculate the y-intercept by substituting x=0 x = 0 into the function:

  • Substitute: f(0)=(0)26(0)+5=5 f(0) = (0)^2 - 6(0) + 5 = 5

This gives the point on the y-axis where the function intersects, which is point C. Thus, point C is at the coordinates (0,5) (0, 5) .

This point matches choice 2 among the provided choices.

Therefore, the solution to the problem is (0,5) (0, 5) .

Answer

(0,5) (0,5)

Exercise #9

The following function has been graphed below:

f(x)=x26x+8 f(x)=x^2-6x+8

Calculate point C.

CCC

Video Solution

Step-by-Step Solution

To solve for point C on the graph of the function f(x)=x26x+8 f(x) = x^2 - 6x + 8 , we will determine the y-intercept of the graph.

According to the properties of a quadratic function, the y-intercept is found by evaluating the function at x=0 x = 0 . This provides the point where the graph crosses the y-axis.

Substituting x=0 x = 0 in the equation:

f(0)=(0)26×0+8=8 f(0) = (0)^2 - 6 \times 0 + 8 = 8

Thus, the y-coordinate of the intercept, and point C, is 8. Hence, point C is located at (0,8) (0, 8) .

Therefore, the solution to the problem is (0,8) (0, 8) .

Answer

(0,8) (0,8)