Khan Academy
Detectable Civilizations in our Galaxy 2
The idea of whether or not communication from other planets can be transmitted and received is discussed in this presentation. The various issues, such as relative stages of development, the ability to receive a transmission, and whether...
Khan Academy
Detectable Civilizations in our Galaxy 1
Sal outlines a framework for detecting possible civilizations in our universe. He considers the number of stars and uses the requirements for civilizations to derive the number of potentially suitable planets. The Drake equation can help...
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Currency Effect on Trade
Delve deeper into currency exchange theory using Sal's hypothetical global trade scenario involving the Chinese Yuan and the US dollar. He references goods manufactured and sold in the countries using supply and demand principles,...
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Currency Effect on Trade Review
Sal reviews the hypothetical global trade scenario from the last video in detail for about the first six minutes, changing a few numbers to make for a cleaner example. He continues the scenario to demonstrate how the natural ups and...
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Correction Calendar Notation
Salman Khan corrects an incorrect calculation from the previous video. It was wrong because there was no actual year zero. He discusses correctly determining the year based on the common AD, BC, or BCE abbreviations.
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Converting to Slope-Intercept Form
This video shows how to graph a linear equation in standard form. He shows three examples of changing each equation into slope-intercept form and graphing it. One example is a line with a negative slope, one is a vertical line, and the...
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Connection Between Even and Odd Numbers and Functions, Algebra II
Are odd numbers connected to odd functions and even numbers to even functions? This video tries to clarify that connection. It also talks about functions that are both odd and even to give a more intuitive feeling about classifying these...
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Conic Sections: Intro to Circles
This video explores the equation of a circle by first looking at the equation of a circle with the center at the origin and then building upon that, equations of circles that are shifted off the origin.
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Identifying Circles and Parabolas from Equations, Conic Sections, Algebra II
This is the last of three well-done videos on identifying and graphing conic sections from an equation. Here, Sal shows how to graph a circle not centered at the origin and a parabola that opens downward.
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Complex Numbers (Part 1)
In this video, a complex number is defined and graphed on the complex plane. Sal also shows how to add, subtract, and multiply two complex numbers. He shows how to divide two complex numbers but runs out of time and continues in the...
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Complex Determinant Example, Imaginary and Complex Numbers, Precalculus
Sal solves a complex determinant problem from the 2010 IIT entrance test. Knowledge of determinants, the exponential form of complex numbers, trigonometric ratios, and algebraic thinking are all utilized here.
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Complex Conjugates, Imaginary and Complex Numbers, Precalculus
Sal discusses the usefulness of the conjugate of the complex number in this video. First, he shows how to add a complex number and its conjugate graphically and algebraically. Then, he shows how to simplify a rational expression with...
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Binomial Theorem (Part 2)
Sal shows two ways to calculate the coefficients of a binomial expansion quickly. The first method shows the relationship between PascalÕs triangle and the coefficients, and the second method shows an even faster way to write the...
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Basic Rate Problem
This video examines a sample rate problem. The listener needs to compute whether four trains, each going different distances over different amounts of time, are moving at the same constant rate. This problem reinforces one's basic...
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Basic Linear Function
This video explores a basic linear cost equation. Given a rate-per-photo and a one-time cost, write a function representing the amount a customer would pay for x number of photos.
Khan Academy
Basic Complex Analysis
This video gives an excellent overview of the different representations of a complex number. First, Sal reviews a pictorial representation of a complex number as an Argand diagram, then shows how to find the modulus and the argument of a...
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Averages, Linear Equations, Algebra I
Sal instructs the class on calculating an average using a real-life example of exam scores. He further demonstrates how to calculate what future scores would be needed to attain the desired average score by the end of the term.
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Area of Inscribed Equilateral Triangle (Some Basic Trig Used)
Delving into basic trigonometry, this resource shows how to find the area of an inscribed equilateral triangle. Using a high-level problem, HeronÕs theorem is used to find the area of a figure. Before SAT testing, use this as a review.
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Area of Diagonal Generated Triangles of Rectangle Are Equal, Geometry
This lecture explores finding the area of each of the triangles created by drawing two diagonal lines through a rectangle. It provides a detailed explanation of how to use a formula to solve the given problem. Tip: Use this for test...
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Area of a Circle, Perimeter, Area, and Volume, Geometry
This production, the second installment in a series of circles, demonstrates the process of finding the area of a circle. It is effective as an introductory tool. However, it needs to explain the reasoning behind the formula because that...
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Angles of Parallel Lines 2, Angles and Intersecting Lines, Geometry
This resource explores parallel lines and requires students to practice calculations and analyze angles. By asking viewers to decide whether two lines are parallel based on the information given, this second part of the parallel lines...
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Algebraic Word Problem
For most people, solving word problems takes a lot of work. But Sal makes it look simple! Follow along as he unpacks this complicated word problem. He even demonstrates how to answer. Excellent!
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Algebra: Slope and Y-Intercept Intuition
Here is an introductory lesson to help you understand the slope of a line, whether positive or negative and the y-intercept's meaning. Several examples of changes in slope are shown on a graph, and the instructor relates them to how the...
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Algebra: Linear Equations 4
This is a lesson in solving linear equations. More specifically, students will see how to solve an equation with a variable expression in the denominator of a fraction.