• #### 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.
• #### 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.
• #### Using the Sine and Cosine Addition Formulas to Prove Identities - Problem 3

How to use the sine and cosine addition formulas to prove a difference formula for tangent.
• #### Using the Sine and Cosine Addition Formulas to Prove Identities - Problem 3

How to use the sine and cosine addition formulas to prove a difference formula for tangent.
• #### 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 - Problem 1

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

How to derive the cosine of a difference formula.
• #### The Cosine Addition Formulas - Concept

How to derive the cosine of a difference formula.
• #### 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.
• #### 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 2

How to use the sine and cosine supplementary angle identities.
• #### Using the Sine and Cosine Addition Formulas to Prove Identities - Problem 2

How to use the sine and cosine supplementary angle identities.
• #### The Cosine Addition Formulas - Problem 2

How to derive the cosine of a sum formula and use it to find the cosine of an angle.
• #### The Cosine Addition Formulas - Problem 2

How to derive the cosine of a sum formula and use it to find the cosine of an angle.
• #### The Cosine Addition Formulas - Problem 3

How to evaluate cos(a ? b) and cos(a + b) when you know only sin(a) and cos(b).
• #### The Cosine Addition Formulas - Problem 3

How to evaluate cos(a ? b) and cos(a + b) when you know only sin(a) and cos(b).
• #### The Sine Addition Formulas - Concept

How to derive the sine of a sum formula.