Find the slope of the secant line of the function f(x)=x2−5x+5
(a) On the interval [1,3]
(b) On the interval [1,2]
(c) On the interval [0,1]
(d) Use the slope of the secant lines computed in parts (b) and (c) above to estimate the slope of the tangent line of f(x) at =1

Respuesta :

Answer:

Step-by-step explanation:

Given function is f(x) = x² - 5x + 5

(a). Slope of the secant of the function in the interval [1, 3],

m = [tex]\frac{\triangle y}{\triangle x}[/tex]

For x = 1

[tex]y_1[/tex] = (1)²- 5(1) + 5

[tex]y_1[/tex] = 1

For x = 3,

[tex]y_2[/tex] = (3)² - 5(3) + 5

[tex]y_2[/tex] = 9 - 15 + 5

[tex]y_2[/tex] = -1

Slope 'm' = [tex]\frac{y_2-y_1}{x_2-x_1}[/tex]

m = [tex]\frac{1+1}{1-3}[/tex]

m = -1

(b). Slope of the secant of the function in the interval [1, 2],

m = [tex]\frac{\triangle y}{\triangle x}[/tex]

For x = 1,

[tex]y_1[/tex] = 1 [From part a]

For x = 2,

[tex]y_2=[/tex] (2)² - 5(2) + 5

    = 4 - 10 + 5

    = -1

Slope = [tex]\frac{-1-1}{2-1}[/tex]

          = -2

(c). Slope of the secant of the function in the interval [0, 1]

For x = 0,

[tex]y_1=0-5(0)+5[/tex]

    = 5

For x = 1

[tex]y_2=-1[/tex] [From part (b)]

m = [tex]\frac{5+1}{0-1}[/tex]

   = -6

(d). Derivative of the function 'f',

f'(x) = 2x - 5

At x = 1,

f'(x) = 2(1) - 5

      = -3

Slope of the tangent = -3

a) The slope of the secant line of the function on the interval [1, 3] is -1.

b) The slope of the secant line of the function on the interval [1, 2] is -2.

c) The slope of the secant line of the function on the interval [0, 1] is -4.

d) The estimated slope of the tangent line of [tex]f(x)[/tex] at [tex]x = 1[/tex] is -3.

Procedure - Determination of slopes of secant lines

Let [tex]f(x)[/tex] be a differentiable curve, the slope of a line secant to that curve ([tex]m_{AB}[/tex]) is defined by the following expression:

[tex]m_{AB} = \frac{f(b)-f(a)}{b-a}[/tex], [tex]a \ne b[/tex] (1)

a) On the interval [tex][1,3][/tex]

If we know that [tex]f(x) = x^{2}-5\cdot x + 5[/tex], [tex]a = 1[/tex] and [tex]b = 3[/tex], then the slope of the secant line is:

[tex]m_{AB} = \frac{-1-1}{3-1}[/tex]

[tex]m_{AB} = -1[/tex]

The slope of the secant line of the function on the interval [1, 3] is -1. [tex]\blacksquare[/tex]

b) On the interval [tex][1, 2][/tex]

If we know that [tex]f(x) = x^{2}-5\cdot x + 5[/tex], [tex]a = 1[/tex] and [tex]b = 2[/tex], then the slope of the secant line is:

[tex]m_{AB} = \frac{-1-1}{2-1}[/tex]

[tex]m_{AB} = -2[/tex]

The slope of the secant line of the function on the interval [1, 2] is -2. [tex]\blacksquare[/tex]

c) On the interval [tex][0, 1][/tex]

If we know that [tex]f(x) = x^{2}-5\cdot x + 5[/tex], [tex]a = 0[/tex] and [tex]b = 1[/tex], then the slope of the secant line is:

[tex]m_{AB} = \frac{1-5}{1-0}[/tex]

[tex]m_{AB} = -4[/tex]

The slope of the secant line of the function on the interval [0, 1] is -4. [tex]\blacksquare[/tex]

d) Estimation of the slope at [tex]x = 1[/tex]

The slope of the tangent line of [tex]f(x)[/tex] at [tex]x = 1[/tex] can be estimated by concept of weighted averages, whose application is shown below:

[tex]m = \left(\frac{1-0}{2-0}\right)\cdot (-4) + \left(\frac{2-1}{2-0} \right)\cdot (-2)[/tex]

[tex]m = -3[/tex]

The estimated slope of the tangent line of [tex]f(x)[/tex] at [tex]x = 1[/tex] is -3. [tex]\blacksquare[/tex]

To learn more on secant lines, we kindly invite to check this verified question: https://brainly.com/question/10128640

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