• #### The Midpoint and Distance Formulas in 3D - Problem 4

##### Math›Precalculus›Vectors and Parametric Equations
How to find the center and radius of a sphere when its equation is not in center-radius form by completing the square.
• #### The Midpoint and Distance Formulas in 3D - Problem 3

##### Math›Precalculus›Vectors and Parametric Equations
How to find the equation of the set of points equidistant from two given points.
• #### The Half-Angle Identities - Concept

How to use the power reduction formulas to derive the half-angle formulas.
• #### The Half-Angle Identities - Concept

How to use the power reduction formulas to derive the half-angle formulas.
• #### The Half-Angle Identities - Problem 3

How to use the double-angle formulas for sine and cosine to derive a half-angle formula for tangent.
• #### The Half-Angle Identities - Problem 3

How to use the double-angle formulas for sine and cosine to derive a half-angle formula for tangent.
• #### Derivatives of Logarithmic Functions - Problem 3

##### Math›Calculus›The Derivative
How to use the change of base formula to compute the derivative of log functions of any base.
• #### The Circle - Concept

##### Math›Precalculus›Conic Sections
How to use the distance formula to derive the equation for a circle.
• #### Equation of a Circle - Concept

##### Math›Geometry›Pythagorean Theorem
How to derive the equation for a circle using the distance formula.
• #### Equation of a Circle - Concept

##### Math›Trigonometry›Pythagorean Theorem
How to derive the equation for a circle using the distance formula.
• #### The Circle - Concept

##### Math›Precalculus›Equations of Lines, Parabolas and Circles
How to use the distance formula to derive the equation for a circle.
• #### The Half-Angle Identities - Problem 1

How to use a half-angle formula to evaluate sin(/8).
• #### The Half-Angle Identities - Problem 2

How to use a half-angle formula to evaluate cos(105).
• #### The Half-Angle Identities - Problem 1

How to use a half-angle formula to evaluate sin(/8).
• #### The Circle - Concept

##### Math›Algebra 2›Conic Sections
How to use the distance formula to derive the equation for a circle.
• #### The Half-Angle Identities - Problem 2

How to use a half-angle formula to evaluate cos(105).