Khan Academy: Using Trig to Solve for Missing Information

Sal dissects basic algebraic equations of the form Ax=B. He encourages viewers to fully understand the equations before learning how to manipulate them. Furthermore, he teaches students how to solve the equations systematically. The...

How can you calculate the height of a tree without having to climb it all the way to the top? The sixth installment of an 11-part Math in Science video series demonstrates how to use trigonometry to determine the height of a tree. 

Sal illustrates more involved equations in this last video in a series. It follows "Simple Equations" and "Equations 2". He continues using color-coded markings to help increase students' understanding of a more complicated equation:...

Video lesson introducing l'Hopital's rule as a way to find limits by using derivatives. Gives the formal definition and uses it to solve an example problem. Includes link to additional practice at the top of the video. [8:51]

Determine if different methods are fair or unfair. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

[Free Registration/Login may be required to access all resource tools.] Learn how to use graphs to solve quadratic equations.

Video deriving the double angle formulas for sine and cosine as well as the start of finding the cosine of the opposite of an angle. Reviews basic trigonometric ratio definitions and some basic trigonometric identities. [9:57]

Video expands upon trigonometric identities derived in previous videos. Identities in this lesson include sine and cosine of the opposite of an angle, sine of an angle plus pi divided by two, and the sine of the difference of two angles....

Video showing how to derive two basic trigonometric identities. Includes link to additional practice problems. [9:10]

A video that demonstrates how to write and solve equations for several different types of algebraic word problems. This is another percent example. This video is also found in the strand Algebra: ck12.org. [11:06]