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
Product and Quotient Rules
Problem 3.86
Textbook Question
Given that f(1)=2 and f′(1)=2 , find the slope of the curve y=xf(x) at the point (1, 2).

1
Step 1: Identify the function y = x f(x) and recognize that you need to find the derivative of this function to determine the slope of the curve at a specific point.
Step 2: Use the product rule to differentiate y = x f(x). The product rule states that if you have two functions u(x) and v(x), then the derivative of their product is given by (uv)' = u'v + uv'.
Step 3: Apply the product rule to y = x f(x). Here, u(x) = x and v(x) = f(x). Therefore, the derivative y' = (x)'f(x) + x(f(x))'.
Step 4: Calculate the derivatives: (x)' = 1 and (f(x))' = f'(x). Substitute these into the expression from Step 3 to get y' = 1*f(x) + x*f'(x).
Step 5: Substitute the given values f(1) = 2 and f'(1) = 2 into the derivative expression y' = f(x) + x*f'(x) to find the slope at the point (1, 2).

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Product Rule
The Product Rule is a fundamental differentiation technique used when finding the derivative of a product of two functions. It states that if you have two functions u(x) and v(x), the derivative of their product is given by u'v + uv'. This rule is essential for differentiating the function y = x f(x) in the given problem.
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Derivative
A derivative represents the rate of change of a function with respect to its variable. It provides information about the slope of the tangent line to the curve at any given point. In this context, calculating the derivative of y = x f(x) will allow us to find the slope of the curve at the specific point (1, 2).
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Evaluating Derivatives at a Point
Evaluating derivatives at a specific point involves substituting the x-value of that point into the derivative function. This process yields the slope of the tangent line to the curve at that point. In this case, after applying the Product Rule and finding the derivative, we will substitute x = 1 to determine the slope of the curve y = x f(x) at (1, 2).
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