• #### Midpoint Formula - Concept

##### Math›Algebra 2›Graphs of Linear Equations
How to find the midpoint of two points.
• #### The Quadratic Formula - Problem 11

##### Math›Algebra›Quadratic Equations and Functions
Songs to help remember the quadratic formula.
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• #### The Quadratic Formula - Problem 2

##### Math›Algebra›Quadratic Equations and Functions
How to use the quadratic formula with decimal approximations or simple radical form solutions.
• #### 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 Sine Addition Formulas - Problem 3

How to evaluate sin(a ? b) and sin(a + b) when you know only cos(a) and sin(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).
• #### Other Forms of the Cosine Double-Angle Formula - Concept

How to derive two more cosine double-angle formulas.
• #### 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 Sine Addition Formulas - Problem 3

How to evaluate sin(a ? b) and sin(a + b) when you know only cos(a) and sin(b).
• #### The Quadratic Formula - Problem 7

##### Math›Algebra›Quadratic Equations and Functions
Solving with the Quadratic Formula after dividing by a common factor.
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• #### The Quadratic Formula - Problem 9

##### Math›Algebra›Quadratic Equations and Functions
Derivation of the quadratic formula using completing the square.
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• #### Other Forms of the Cosine Double-Angle Formula - Concept

How to derive two more cosine double-angle formulas.
• #### The Midpoint and Distance Formulas in 3D - Concept

##### Math›Precalculus›Vectors and Parametric Equations
How to derive the formula for the midpoint of a segment in three dimensions.
• #### The Quadratic Formula - Problem 5

##### Math›Algebra›Quadratic Equations and Functions
Tips for solving with the quadratic formula correctly.
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• #### The Midpoint and Distance Formulas in 3D - Problem 1

##### Math›Precalculus›Vectors and Parametric Equations
How to find the length and midpoint of a segment in three dimensions.
• #### The Euler Formula - Problem 2

##### Math›Precalculus›Polar Coordinates and Complex Numbers
How to derive our method for multiplying complex numbers and DeMoivre's Theorem using Euler's Formula.
• #### The Euler Formula - Problem 1

##### Math›Precalculus›Polar Coordinates and Complex Numbers
How to use the Euler Formula to convert a complex number from rectangular form to the exponential form.
• #### The Quadratic Formula - Problem 12

##### Math›Algebra›Quadratic Equations and Functions
Rational solutions from the quadratic formula means factoring would be possible, as well.
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• #### The Quadratic Formula - Problem 13

##### Math›Algebra›Quadratic Equations and Functions
Simplifying radicals in using the quadratic formula to find exact solutions.
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