# 2015 AP Calculus BC 5a | AP Calculus BC solved exams | AP Calculus BC | Khan Academy | Summary and Q&A

11.0K views
β’
April 30, 2016
by
2015 AP Calculus BC 5a | AP Calculus BC solved exams | AP Calculus BC | Khan Academy

## TL;DR

The video explains how to find the equation for the tangent line to a function at a specific point.

## Key Insights

• π The equation of a tangent line is in the form y = mx + b, where m is the slope and b is the y-intercept.
• βΊοΈ Evaluating the derivative of the function at the given x-coordinate gives us the slope of the tangent line.
• β£οΈ The y-coordinate of the point on the graph corresponds to the value of the function at that x-coordinate.
• π Substituting the slope and the point into the equation y = mx + b allows us to solve for the y-intercept.
• π«₯ The tangent line represents the best linear approximation to the function at the given point.
• π«₯ Tangent lines can be used to estimate the behavior of the function near the point of tangency.
• π₯ The steepness of the slope indicates how quickly the function is changing at that point.

## Transcript

• [Voiceover] Consider the function f of x is equal to one over x-squared minus k-x, where k is a nonzero constant. The derivative of f is given by, and they give us this expression right over here. That's nice that they took the derivative for us. Now part a, let k equals three so that f of x is equal to one over x-squared minus three-x. So they s... Read More

### Q: What is the purpose of finding the equation for a tangent line to a function?

Finding the equation of a tangent line allows us to determine the instantaneous rate of change of the function at a specific point. It provides valuable information about the behavior of the function in the vicinity of that point.

### Q: How is the slope of the tangent line determined?

The slope of the tangent line is determined by evaluating the derivative of the function at the given x-coordinate. This gives us the rate at which the function is changing at that point.

### Q: What is the significance of the y-intercept of the tangent line?

The y-intercept of the tangent line represents the value of the function at the given x-coordinate. It helps us determine the specific point on the graph of the function where the tangent line touches.

### Q: Can the process shown in the video be applied to any function?

Yes, the process of finding the equation for a tangent line can be applied to any function, as long as the derivative of the function exists at the given point.

## Summary & Key Takeaways

• The video demonstrates how to find the equation of a tangent line to a function at a specific point.

• It explains the process of finding the slope of the tangent line using the derivative of the function.

• The video also shows how to determine the y-intercept of the tangent line by evaluating the function at the given x-coordinate.