Table of contents
- 0. Functions7h 52m
- Introduction to Functions16m
- Piecewise Functions10m
- Properties of Functions9m
- Common Functions1h 8m
- Transformations5m
- Combining Functions27m
- Exponent rules32m
- Exponential Functions28m
- Logarithmic Functions24m
- Properties of Logarithms34m
- Exponential & Logarithmic Equations35m
- Introduction to Trigonometric Functions38m
- Graphs of Trigonometric Functions44m
- Trigonometric Identities47m
- Inverse Trigonometric Functions48m
- 1. Limits and Continuity2h 2m
- 2. Intro to Derivatives1h 33m
- 3. Techniques of Differentiation3h 18m
- 4. Applications of Derivatives2h 38m
- 5. Graphical Applications of Derivatives6h 2m
- 6. Derivatives of Inverse, Exponential, & Logarithmic Functions2h 37m
- 7. Antiderivatives & Indefinite Integrals1h 26m
- 8. Definite Integrals4h 44m
- 9. Graphical Applications of Integrals2h 27m
- 10. Physics Applications of Integrals 2h 22m
3. Techniques of Differentiation
Basic Rules of Differentiation
Problem 67b
Textbook Question
Let f(x) = 4√x - x.
Find all points on the graph of f at which the tangent line has slope -1/2.

1
Step 1: Find the derivative of the function f(x) = 4\sqrt{x} - x. The derivative, f'(x), represents the slope of the tangent line at any point x on the graph of f.
Step 2: Set the derivative equal to the given slope of the tangent line, which is -1/2. This will give you an equation to solve for x: f'(x) = -1/2.
Step 3: Solve the equation from Step 2 for x. This will give you the x-coordinates where the slope of the tangent line is -1/2.
Step 4: Substitute the x-values found in Step 3 back into the original function f(x) to find the corresponding y-coordinates. This will give you the points (x, y) on the graph.
Step 5: Verify the points by checking that the derivative at these x-values indeed equals -1/2, ensuring the solution is correct.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Derivative
The derivative of a function measures the rate at which the function's value changes as its input changes. It is represented as f'(x) and provides the slope of the tangent line to the graph of the function at any given point. To find points where the tangent line has a specific slope, we need to compute the derivative and set it equal to that slope.
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Tangent Line
A tangent line to a curve at a given point is a straight line that touches the curve at that point without crossing it. The slope of the tangent line is equal to the derivative of the function at that point. In this problem, we are looking for points on the graph of f where the slope of the tangent line equals -1/2.
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Finding Critical Points
Finding critical points involves determining where the derivative of a function is zero or undefined. These points are essential for analyzing the behavior of the function, including identifying where the slope of the tangent line meets specific criteria, such as -1/2 in this case. Solving the equation derived from the derivative will yield the x-values of interest.
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