Khan Academy Static

The_unit_circle_definition_of_sine_cosine_and_tangent

Learn how the trigonometric ratios are extended to all real numbers using algebra. Start solving simple problems that involve this new definition of the trigonometric functions.

Basic_trigonometric_identities

Learn about very useful trigonometric identities that arise by considering different properties of the unit circle definition.

Introduction_to_radians

Learn about radians, which are the official unit of measurement for angles in algebra (in contrast to degrees, which are used in geometry).

Finding_amplitude_and_midline_of_sinusoidal_functions_from_their_formulas

Learn how to find the amplitude and the midline of the graph of a sinusoidal function from its formula. For example, find the amplitude and the midline of f(x)=3*sin(2x-1)+5.

Graphing_sinusoidal_functions

Learn how to draw the graph of sinusoidal functions. For example, draw the graph of f(x)=-2*cos(πx)-7.

The_graphs_of_sine_cosine_and_tangent

Learn how the graphs of y=sin(θ), y=cos(θ), and y=tan(θ) look, using the unit circle definition of the functions.

Trigonometric_values_of_special_angles

Learn how to find the trigonometric values of some special angles without the use of a calculator.

Constructing_sinusoidal_functions

Learn how to find the formula of a sinusoidal function from its graph or a few selected features. Model real-world situations with sinusoidal functions.

Introduction_to_amplitude_midline_and_extrema_of_sinusoidal_functions

Learn about very important features of sinusoidal functions: the amplitude and the midline. Learn how they relate to the extremum points of the function.

The_Pythagorean_identity

Prove the Pythagorean trigonometric identity for all real numbers and use it in order to solve problems.

Period_of_sinusoidal_functions

Learn about the period of sinusoidal functions: how it relates to extremum points and the midline, and how to find it from the formula of the function. For example, find the period of f(x)=3*sin(2x-1)+5.