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Ch. 3 - Derivatives
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoHass 15th EditionCh. 3 - DerivativesProblema 3.77
Capitolo 3, Problema 3.77

Find the points on the curve y = tan x, -π/2 < x < π/2, where the normal line is parallel to the line y = -x/2. Sketch the curve and normal lines together, labeling each with its equation.

Guida verificata passo dopo passo
1
Identify the slope of the given line y = -x/2. The slope is -1/2.
Find the derivative of the curve y = tan(x) to determine the slope of the tangent line at any point x. The derivative is dy/dx = sec^2(x).
Since the normal line is perpendicular to the tangent line, the slope of the normal line is the negative reciprocal of the tangent line's slope. Set the slope of the normal line equal to -1/2 to find the x-values where this condition holds.
Solve the equation -1/(sec^2(x)) = -1/2 to find the x-values. This simplifies to sec^2(x) = 2, which further simplifies to cos^2(x) = 1/2.
Solve for x in the interval -π/2 < x < π/2 where cos^2(x) = 1/2. These x-values are the points where the normal line is parallel to y = -x/2. Use these x-values to find the corresponding y-values on the curve y = tan(x).

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Derivative of a Function

The derivative of a function at a point gives the slope of the tangent line to the curve at that point. For the function y = tan(x), the derivative is y' = sec^2(x). Understanding this concept is crucial for finding where the tangent line has a specific slope, which is necessary for determining where the normal line is parallel to a given line.
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06:30
Derivatives of Other Trig Functions

Normal Line to a Curve

A normal line to a curve at a given point is a line perpendicular to the tangent line at that point. If the slope of the tangent line is m, the slope of the normal line is -1/m. In this problem, we need to find where the normal line has a slope of -1/2, which means the tangent line must have a slope of 2.
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Percorso guidato
05:13
Slopes of Tangent Lines

Parallel Lines

Parallel lines have the same slope. In this problem, the normal line must be parallel to the line y = -x/2, which has a slope of -1/2. By setting the slope of the normal line equal to -1/2, we can find the points on the curve where this condition is satisfied, helping us solve the problem.
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Percorso guidato
05:13
Slopes of Tangent Lines
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Derivative Calculations


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