Chapter 11: Problem 9
Find the slope of the tangent to the curve at the indicated point. $$\begin{aligned} &y=\sqrt{x} ;(4,2)\\\ &\text { Hint: } x-4=(\sqrt{x}-2)(\sqrt{x}+2) \end{aligned}$$
Short Answer
Expert verified
The slope of the tangent is \( \frac{1}{4} \).
Step by step solution
01
Differentiate the Function
To find the slope of the tangent to the curve, we need to differentiate the function. Given, \( y = \sqrt{x} \), first express it as a power: \( y = x^{1/2} \). The derivative, \( \frac{dy}{dx} \), is \( \frac{1}{2}x^{-1/2} \) which simplifies to \( \frac{1}{2\sqrt{x}} \).
02
Evaluate the Derivative at the Point
We need to find the slope at the point (4, 2). Substitute \( x = 4 \) into the derivative: \( \frac{1}{2\sqrt{4}} = \frac{1}{2 \times 2} = \frac{1}{4} \).
03
Confirm the Point Lies on the Curve
Verify that (4, 2) is actually a point on the curve \( y = \sqrt{x} \). We substitute \( x = 4 \) into the original function to get \( y = \sqrt{4} = 2 \). The point (4, 2) does lie on the curve.
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Derivative
In calculus, the concept of a derivative is fundamental. It gives us a tool to measure how a function changes as its input changes. In the context of a graph, the derivative at a particular point is the slope of the tangent line to the graph at that point.
When we look at a function, such as \( y = \sqrt{x} \), we're interested in how \( y \) grows as \( x \) increases. To find this rate of change, we differentiate the function. Differentiation tells us the derivative, which is a formula that describes the slope at any point \( x \) on the curve.
When we look at a function, such as \( y = \sqrt{x} \), we're interested in how \( y \) grows as \( x \) increases. To find this rate of change, we differentiate the function. Differentiation tells us the derivative, which is a formula that describes the slope at any point \( x \) on the curve.
- For \( y = \sqrt{x} \), first express it as a power, \( y = x^{1/2} \).
- The derivative, \( \frac{dy}{dx} \), measures how \( y \) changes with respect to \( x \), yielding \( \frac{1}{2x^{1/2}} = \frac{1}{2\sqrt{x}} \).
Slope of tangent
The slope of the tangent to a curve at a specific point gives us the direction of the curve at that exact location.
The tangent line just "touches" the curve at a single point without crossing it, representing the instantaneous rate of change.
For practical understanding, think of a straight road that gently kisses the side of a curved path without actually going off into the grass or turning back onto the curved path.
Using our derivative \( \frac{1}{2\sqrt{x}} \), we can substitute the \( x \)-value of the point of interest to find this slope.
The tangent line just "touches" the curve at a single point without crossing it, representing the instantaneous rate of change.
For practical understanding, think of a straight road that gently kisses the side of a curved path without actually going off into the grass or turning back onto the curved path.
Using our derivative \( \frac{1}{2\sqrt{x}} \), we can substitute the \( x \)-value of the point of interest to find this slope.
- For the point \((4, 2)\), substitute \( x = 4 \).
- The slope becomes \( \frac{1}{2\sqrt{4}} = \frac{1}{4} \).
Differentiation
Differentiation is the process of finding the derivative of a function.
It involves applying rules that simplify the function to its rate of change formula.
In our exercise, this meant converting \( y = \sqrt{x} \) into a simpler power form (like \( x^{1/2} \)) to make differentiation straightforward.
Through applying the power rule,
It involves applying rules that simplify the function to its rate of change formula.
In our exercise, this meant converting \( y = \sqrt{x} \) into a simpler power form (like \( x^{1/2} \)) to make differentiation straightforward.
Through applying the power rule,
- When differentiating, decrease the exponent by one and multiply by the original exponent.
- For \( x^{1/2} \), the derivative is \( \frac{1}{2}x^{-1/2} = \frac{1}{2\sqrt{x}} \).
Mathematics education
In mathematics education, teaching calculus concepts like derivatives and slopes of tangents enhances students' problem-solving skills.
These concepts not only apply to academia but also to real-life scenarios, helping students understand the world around them.
In teaching differentiation and slope of tangents:
These concepts not only apply to academia but also to real-life scenarios, helping students understand the world around them.
In teaching differentiation and slope of tangents:
- Instructors emphasize understanding the underlying principles, not just mechanical applications.
- Visual aids, such as graphing software or drawn graphs, show students the real-world applications and representations.
- Exercises like finding slopes at specific points help build intuitive understanding alongside theoretical knowledge.