Chapter 2: Problem 46
Find an equation of the line \(/\) tangent to the graph of \(f\) at the given point. $$ f(x)=\sqrt{x} ;(16,4) $$
Short Answer
Expert verified
The tangent line equation is \(y = \frac{1}{8}x + 2\).
Step by step solution
01
Differentiate the Function
To find the tangent line, we need the derivative of the function because the derivative at a point gives the slope of the tangent. Given the function \(f(x) = \sqrt{x} \), rewrite it as \(f(x) = x^{1/2}\). Differentiate \(f(x)\) to find \(f'(x)\):\[ f'(x) = \frac{1}{2}x^{-1/2} = \frac{1}{2\sqrt{x}} \]
02
Evaluate the Derivative at Given Point
Substitute \(x = 16\) into the derivative to find the slope of the tangent line at \((16, 4)\):\[ f'(16) = \frac{1}{2\sqrt{16}} = \frac{1}{2 \times 4} = \frac{1}{8} \]
03
Use Point-Slope Form of a Line
With the slope \(m = \frac{1}{8}\) and the point \((16, 4)\), we use the point-slope form of a line, \(y - y_1 = m(x - x_1)\), to find the equation of the tangent line:\[ y - 4 = \frac{1}{8}(x - 16) \]
04
Simplify the Equation of the Tangent Line
Simplify the equation to put it in slope-intercept form \(y = mx + b\):\[ y - 4 = \frac{1}{8}x - 2 \ y = \frac{1}{8}x + 2 \]
05
Conclusion: Equation of the Tangent Line
The equation of the line tangent to \(f(x) = \sqrt{x}\) at the point \((16, 4)\) is \(y = \frac{1}{8}x + 2\).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Tangent Line
A tangent line is a straight line that just "touches" a curve at a particular point, without cutting across the curve. Think of it as the line that best approximates the curve at that point. It provides a snapshot of the curve's direction. For a given function, such as \( f(x) = \sqrt{x} \), the tangent line at a specific point provides the best linear approximation of the function near that point.
- In our case, the point is \((16, 4)\).
- The tangent line visually represents how the function behaves precisely at the point \((16, 4)\).
Derivative
The derivative of a function measures how the function's output (or \( y \)-value) changes as its input (or \( x \)-value) changes. It is essentially the function's rate of change or slope at each point.
- The notation used for the derivative is \( f'(x) \).
- For \( f(x) = \sqrt{x} \), the derivative \( f'(x) \) is \( \frac{1}{2\sqrt{x}} \).
Slope
The slope of a line is a measure of its steepness. It is calculated as the "rise over run," that is, the change in \( y \) over the change in \( x \). For tangent lines, the slope at a specific point on a curve is found by evaluating the derivative at that point.
- The slope of the tangent line for our function at \((16, 4)\) is \( \frac{1}{8} \).
Point-Slope Form
The point-slope form is a linear equation format used to describe the equation of a line when a point on the line and the slope are known. The formula is:\[ y - y_1 = m(x - x_1) \]where \((x_1, y_1)\) is a point on the line, and \( m \) is the slope of the line.
- For the point \((16, 4)\) with a slope of \( \frac{1}{8} \), the equation becomes \( y - 4 = \frac{1}{8}(x - 16) \).