# Trigonometric functions

Contents

Learn about the definition of the basic trigonometric functions (sin(x), cos(x), and tan(x)), and use advanced trigonometric functions for various purposes.

12 exercises available

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

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.

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

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

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

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

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

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.

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.

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

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.