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 Integrals3h 25m
3. Techniques of Differentiation
Basic Rules of Differentiation
Problem 61a
Textbook Question
{Use of Tech} Equations of tangent lines
Find an equation of the line tangent to the given curve at a.
y = ex; a = ln 3

1
First, identify the function given in the problem. The function is \( y = e^x \).
To find the equation of the tangent line, we need the derivative of the function, which represents the slope of the tangent line at any point \( x \). The derivative of \( y = e^x \) is \( \frac{dy}{dx} = e^x \).
Evaluate the derivative at the given point \( a = \ln 3 \). Substitute \( x = \ln 3 \) into the derivative to find the slope of the tangent line: \( m = e^{\ln 3} \).
Calculate the y-coordinate of the point on the curve where \( x = \ln 3 \). Substitute \( x = \ln 3 \) into the original function: \( y = e^{\ln 3} \).
Use the point-slope form of the equation of a line, \( y - y_1 = m(x - x_1) \), where \( (x_1, y_1) \) is the point on the curve and \( m \) is the slope. Substitute \( x_1 = \ln 3 \), \( y_1 = e^{\ln 3} \), and \( m = e^{\ln 3} \) to write the equation of the tangent line.

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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 represents the instantaneous rate of change of the function at that point, which can be found using the derivative of the function.
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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 = e^x, the derivative is also e^x, which simplifies the process of finding the slope of the tangent line.
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Exponential Function
An exponential function is a mathematical function of the form y = a * b^x, where 'a' is a constant, 'b' is the base of the exponential, and 'x' is the exponent. The function y = e^x is a specific case where the base 'e' is the natural logarithm base, and it has unique properties, such as its derivative being equal to itself, which is crucial for finding tangent lines.
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