• #### The Double-Angle Formulas - Problem 1

How to use the sine and cosine double-angle formulas to find sin(2a) and cos(2a) when sin(a) is known.
• #### Using the Inverse Trigonometric Functions - Concept

How to evaluate expressions like tan(sin (4/5))^(-1).
• #### Using the Inverse Trigonometric Functions - Concept

How to evaluate expressions like tan(sin (4/5))^(-1).
• #### Using the Inverse Trigonometric Functions - Problem 1

How to prove an identity that involves sin^-1(x) and cos^-1(x).
• #### Using the Inverse Trigonometric Functions - Problem 1

How to prove an identity that involves sin^-1(x) and cos^-1(x).
• #### The Euler Formula - Problem 3

##### Math›Precalculus›Polar Coordinates and Complex Numbers
How to derive two trigonometric identities using Euler's Formula.
• #### Navigation Problems - Problem 3

##### Math›Precalculus›Vectors and Parametric Equations
How we find the course and groundspeed of an airplane when we are given its velocity and the wind velocity.
• #### Navigation Problems - Problem 2

##### Math›Precalculus›Vectors and Parametric Equations
How we find the course and groundspeed of a complicated airplane problem when we are given its velocity and the wind velocity at 210 and 270 degrees.
• #### Using Trigonometric Identities - Concept

##### Math›Trigonometry›Trigonometric Functions
How to simplify a trigonometric expression by converting to sines and cosines and using algebra.
• #### Using Trigonometric Identities - Concept

##### Math›Precalculus›Trigonometric Functions
How to simplify a trigonometric expression by converting to sines and cosines and using algebra.
• #### Trigonometric Ratios: Cosine - Problem 1

##### Math›Geometry›Basic Trigonometry
How to find the sine of an angle in a right triangle.
• #### Trigonometric Identities - Problem 1

##### Math›Precalculus›Trigonometric Functions
How to use the Pythagorean identity to find cosine and tangent when sine is known.
• #### Trigonometric Identities - Problem 1

##### Math›Trigonometry›Trigonometric Functions
How to use the Pythagorean identity to find cosine and tangent when sine is known.
• #### Trigonometric Ratios: Cosine - Concept

##### Math›Trigonometry›Basic Trigonometry
How to define the cosine ratio and identify the cosine of an angle in a right triangle.
• #### Transforming the Tangent Graph - Concept

##### Math›Precalculus›Trigonometric Functions
How to graph y = tan(q) for one or more periods.
• #### Inverse Trigonometric Functions - Concept

##### Math›Geometry›Basic Trigonometry
How to use inverse trig functions to find angles in right triangles.
• #### Trigonometric Ratios: Cosine - Concept

##### Math›Geometry›Basic Trigonometry
How to define the cosine ratio and identify the cosine of an angle in a right triangle.
• #### Trigonometric Ratios: Tangent - Concept

##### Math›Precalculus›Basic Trigonometry
How to define the tangent ratio and identify the tangent of an angle in a right triangle.
• #### Trigonometric Ratios: Cosine - Concept

##### Math›Precalculus›Basic Trigonometry
How to define the cosine ratio and identify the cosine of an angle in a right triangle.
• #### Transforming the Tangent Graph - Concept

##### Math›Trigonometry›Trigonometric Functions
How to graph y = tan(q) for one or more periods.