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
The Chain Rule
Problem 92
Textbook Question
{Use of Tech} Tangent lines Determine equations of the lines tangent to the graph of y= x√5−x² at the points (1, 2) and (−2,−2). Graph the function and the tangent lines.

1
Step 1: Find the derivative of the function y = x\sqrt{5-x^2}. Use the product rule and chain rule to differentiate y with respect to x.
Step 2: Evaluate the derivative at the point (1, 2) to find the slope of the tangent line at this point. Substitute x = 1 into the derivative to get the slope.
Step 3: Use the point-slope form of a line, y - y_1 = m(x - x_1), where m is the slope found in Step 2 and (x_1, y_1) is the point (1, 2), to write the equation of the tangent line at (1, 2).
Step 4: Repeat Steps 2 and 3 for the point (-2, -2). Evaluate the derivative at x = -2 to find the slope of the tangent line at this point, and use the point-slope form to write the equation of the tangent line.
Step 5: Graph the original function y = x\sqrt{5-x^2} and the two tangent lines found in Steps 3 and 4 on the same set of axes to visualize the function and its tangent lines at the given points.

This video solution was recommended by our tutors as helpful for the problem above
Video duration:
9mPlay a video:
Was this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
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, which represents the instantaneous rate of change of the function. To find the equation of the tangent line, we use the point-slope form of a line, which requires the slope and the coordinates of the point of tangency.
Recommended video:
Slopes of Tangent Lines
Derivative
The derivative of a function measures how the function's output value changes as its input value changes. It is defined as the limit of the average rate of change of the function over an interval as the interval approaches zero. For the function y = x√(5 - x²), the derivative can be calculated using the product and chain rules, which will provide the slope needed for the tangent lines at specific points.
Recommended video:
Derivatives
Graphing Functions
Graphing a function involves plotting its output values against its input values on a coordinate plane. This visual representation helps in understanding the behavior of the function, including its intercepts, increasing/decreasing intervals, and points of tangency. For the given function, graphing it alongside the tangent lines allows for a clear visual comparison of how the tangent lines relate to the curve at the specified points.
Recommended video:
Graph of Sine and Cosine Function
Watch next
Master Intro to the Chain Rule with a bite sized video explanation from Callie
Start learningRelated Videos
Related Practice