####
Now... gain access to over
**2 Million**
curated educational videos and
**500,000**
educator reviews to free & open educational resources

### We found 11,394 reviewed resources

Lesson Planet

#### Patterns in Sequences 2

This video looks again at finding the algebraic pattern in sequences. In the example, we are looking at a figure where a number of toothpicks (or lines) are added each time, and you need to find how many toothpicks will be in the 50th...

Lesson Planet

#### Patterns in Sequences 1

Faced with a series of numbers we need to find the next few values of the sequence. This short video shows an example of finding the next values in a sequence where we need to find the pattern of adding a specific number each time to...

Lesson Planet

#### Parallel Lines 2

Can you tell, algebraically, if three lines are parallel? In this video, Sal demonstrates how to rewrite linear equations in slope-intercept form and compare the slope of each line.

Lesson Planet

#### Parabola Focus and Directrix 1

Starting with a point (focus) and a line below the point (directrix), in this video, Sal tries to find the set of all points (locus) equidistant to the point and the line. He shows, using the distance formula, that indeed, we have an...

Lesson Planet

#### Introduction to Logarithms Properties

Sal gets to the heart of the matter in this video, clarifying that it's important to understand math "so you can actually apply it in life later on and not have relearn everything every time." True to his word, Sal demonstrates ways to...

Lesson Planet

#### Introduction to Limits (HD)

Sal begins his explanation of limits with a few basic examples and takes a more intuitive point of view before looking at a formal mathematical definition in later videos. He starts by introducing the notation for limits and describes...

Lesson Planet

#### Introduction to Interest

Here is a simple tutorial on the difference between simple and compound interest. In it, Sal describes what interest is, defines the vocabulary of principle and interest rate. He also models year-by-year the amount of money owed under...

Lesson Planet

#### Introduction to Function Inverses

Starting from a brief look at functions and the mapping of domains to ranges, Sal starts out with an intuitive sense of what a function inverse is. He then, using an example, shows how to find the inverse of a function and also shows how...

Lesson Planet

#### Intro to 30-60-90 Triangles

As the fourth part of a series on the Pythagorean Theorem, Sal continues an exploration of the ways to calculate the length of sides of a right triangle using algebra. He also explores using this theorem to solve problems involving a...

Lesson Planet

#### Identifying Conics 2

In this video, Sal shows again how to write an equation of a conic section in standard form and identify the conic section it represents. This time, his example is of a hyperbola (not centered at the origin), which he also graphs.

Lesson Planet

#### Identifying Conics 1

After watching this video, you should be able to write an equation of a conic section in standard form, and identify the conic section from its equation. In an example problem, Sal reviews how to complete the square and graph an ellipse...

Lesson Planet

#### Fun Trig Problem

If solving trigonometric equations is your idea of fun, then this video is correctly titled. Here Sal uses trigonometric identities, the quadratic formula, and inverse trigonometric functions to solve a trigonometric equation sent in by...

Lesson Planet

#### Focus and Directrix of a Parabola 2

Continuing from a previous video, Sal takes the discussion of the focus and directrix of parabola further. Given the parabola, y=x2, he derives the focus and directrix by matching parts of the equation he found earlier. He then, comes up...

Lesson Planet

#### Foci of an Ellipse

The foci of an ellipse are explored in this video. First, foci are shown as the two points on the major axis such that the sum of the distance from a point on the ellipse and the foci points is the same as the distance from any point on...

Lesson Planet

#### Foci of a Hyperbola

In this video, Sal defines the vertex and the foci of a hyperbola, and shows how to locate both. By comparing the hyperbola to an ellipse throughout the video, the listener sees the similarities between these two conic sections. This...

Lesson Planet

#### Finding the 100th Term in a Sequence

The example problem is this video has a sequence of numbers that decrease by a fixed amount with each iteration, and one needs to find the 100th number in the sequence. Sal shows the listener how to find the pattern between the number...