Final answer:
To determine the equation of the normal line to the parabola y=x² - 8x + 2, which is parallel to the line x - 4y = 4, first find the slope of the given line (¼). Then, find where the slope of the parabola's tangent is -4, leading to the point (2, -10). Finally, use the slope (¼) and point (2, -10) to write the normal line's equation: y = ¼x - 10.5.
Step-by-step explanation:
To find an equation of the normal line to the parabola y=x² − 8x + 2 that is parallel to the line x − 4y = 4, we first need to find the slope of the given line.
We can rewrite the line's equation in slope-intercept form as y = ¼x - 1.
This reveals that the slope of the line is ¼.
Because the normal line we want to find is parallel to this line, it will also have a slope of ¼.
Next, we take the derivative of the parabola's equation to find the slope at any point on the parabola, which gives y' = 2x - 8.
We need to find the value of x where the slope of the tangent to the parabola is the negative reciprocal of ¼, which is -4, since the normal line is perpendicular to the tangent.
By setting 2x - 8 = -4, we solve for x and find that x = 2.
After finding the x-coordinate, we substitute x = 2 into the original parabola equation to get the y-coordinate, which gives us y = 2² - 8(2) + 2 = -10.
With the point (2, -10) on the normal line and the slope of ¼, we use the point-slope form of a line to write the equation of the normal line. The equation is y + 10 = ¼(x - 2).
Simplifying, we get the final equation of the normal line: y = ¼x - ¼(2) - 10,
which simplifies to y = ¼x - ¼ - 10, or y = ¼x - 10.5.