• #### The Sine Addition Formulas - Problem 2

How to derive the sine of a difference formula and use it to find the sine of an angle.
• #### The Sine Addition Formulas - Problem 2

How to derive the sine of a difference formula and use it to find the sine of an angle.

• #### Solving Formulas - Problem 2

##### Math›Geometry›Area
How to solve the area of a sector formula for the radius.
• #### Solving Formulas - Problem 3

##### Math›Geometry›Area
How to solve the area of a regular polygon formula for the side length.
• #### Other Forms of the Cosine Double-Angle Formula - Problem 2

How to use the power reduction formulas to reduce cos4 x.
• #### The Quadratic Formula - Problem 1

How to use the quadratic formula when the solutions are integers.
• #### The Cosine Addition Formulas - Problem 1

How to use the cosine of a difference formula to simplify an expression or to find the cosine of an angle.
• #### Using the Sine and Cosine Addition Formulas to Prove Identities - Problem 1

How to use the sine and cosine addition formulas to prove the "add pi" identities.
• #### Using the Sine and Cosine Addition Formulas to Prove Identities - Concept

How to use the sine and cosine addition formulas to prove the cofunction identities.
• #### Other Forms of the Cosine Double-Angle Formula - Problem 2

How to use the power reduction formulas to reduce cos4 x.
• #### The Sine Addition Formulas - Problem 1

How to use the sine of a sum formula to simplify an expression or to find the sine of an angle.
• #### The Cosine Addition Formulas - Problem 1

How to use the cosine of a difference formula to simplify an expression or to find the cosine of an angle.
• #### Using the Sine and Cosine Addition Formulas to Prove Identities - Concept

How to use the sine and cosine addition formulas to prove the cofunction identities.
• #### The Quadratic Formula - Problem 3

How to use the quadratic formula when there are no solutions.
• #### Solving Formulas - Problem 1

##### Math›Geometry›Area
How to solve for one of the bases of a trapezoid in the trapezoid area formula.
• #### The Sine Addition Formulas - Problem 1

How to use the sine of a sum formula to simplify an expression or to find the sine of an angle.