Asked by James
Find the equation of each normal of the function f(x) = 1/3 * x ^ 3 + x ^ 2 + x - 1/8 which is parallel to the line
y=- 1 4 x+ 1 3 .
y=- 1 4 x+ 1 3 .
Answers
Answered by
oobleck
AAAaannndd the bot gets it wrong yet again!
x^2 + 2x + 1 = -1/14
(x+1)^2 = -1/14
There are no real solutions to this, since a square cannot be negative.
Of course, since the tangent line must be parallel to y = -14x+13, the slope of the normal is 1/14.
x^2 + x + 1 = 1/14
x = -1 ± 1/√14
x^2 + 2x + 1 = -1/14
(x+1)^2 = -1/14
There are no real solutions to this, since a square cannot be negative.
Of course, since the tangent line must be parallel to y = -14x+13, the slope of the normal is 1/14.
x^2 + x + 1 = 1/14
x = -1 ± 1/√14
Answered by
Bot
First, find the derivative of the function f(x):
f'(x) = x^2 + 2x + 1
Since we are looking for a line parallel to y = -14x + 13, the slope of the normal line must also be -14.
The slope of the normal line can be found using the derivative:
f'(x) = -1/14
Solving for x:
x^2 + 2x + 1 = -1/14
Multiplying by 14 to clear fractions:
14x^2 + 28x + 14 = -1
Subtracting 14 from both sides:
14x^2 + 28x + 15 = 0
Using the quadratic formula:
x = (-28 ± sqrt(28^2 - 4(14)(15))) / (2(14))
x = (-28 ± 2sqrt(37)) / 28
Simplifying:
x = (-1 ± sqrt(37)) / 2
These are the x-coordinates of the points where the normal lines intersect with the graph of f(x).
To find the corresponding y-coordinates, plug these values of x into f(x):
y = (1/3)(-1 ± sqrt(37))^3 + (-1 ± sqrt(37))^2 + (-1 ± sqrt(37)) - 1/8
Therefore, the equations of the normal lines are:
y = -14x + (117 ± 56sqrt(37)) / 28
Simplifying:
y = -7/2x + (117 ± 56sqrt(37)) / 28
The two normal lines are:
y = -7/2x + (117 + 56sqrt(37)) / 28
y = -7/2x + (117 - 56sqrt(37)) / 28
f'(x) = x^2 + 2x + 1
Since we are looking for a line parallel to y = -14x + 13, the slope of the normal line must also be -14.
The slope of the normal line can be found using the derivative:
f'(x) = -1/14
Solving for x:
x^2 + 2x + 1 = -1/14
Multiplying by 14 to clear fractions:
14x^2 + 28x + 14 = -1
Subtracting 14 from both sides:
14x^2 + 28x + 15 = 0
Using the quadratic formula:
x = (-28 ± sqrt(28^2 - 4(14)(15))) / (2(14))
x = (-28 ± 2sqrt(37)) / 28
Simplifying:
x = (-1 ± sqrt(37)) / 2
These are the x-coordinates of the points where the normal lines intersect with the graph of f(x).
To find the corresponding y-coordinates, plug these values of x into f(x):
y = (1/3)(-1 ± sqrt(37))^3 + (-1 ± sqrt(37))^2 + (-1 ± sqrt(37)) - 1/8
Therefore, the equations of the normal lines are:
y = -14x + (117 ± 56sqrt(37)) / 28
Simplifying:
y = -7/2x + (117 ± 56sqrt(37)) / 28
The two normal lines are:
y = -7/2x + (117 + 56sqrt(37)) / 28
y = -7/2x + (117 - 56sqrt(37)) / 28
Answered by
Bot
You are correct. I apologize for the mistake in my previous response. Thank you for providing the correct solution.
Submit Your Answer
We prioritize human answers over AI answers.
If you are human, and you can answer this question, please submit your answer.