the half angle formulas 36 videos

The HalfAngle Identities
Precalculus Advanced Trigonometry
How to use the power reduction formulas to derive the halfangle formulas.
the power reduction formulas the half angle formulas quadrants 
The DoubleAngle Formulas
Precalculus Advanced Trigonometry
How to use the sine and cosine addition formulas to prove the doubleangle formulas.
the sine of a sum formula the cosine of a sum formula the sine double angle formula the cosine double angle formula 
Other Forms of the Cosine DoubleAngle Formula
Precalculus Advanced Trigonometry
How to derive two more cosine doubleangle formulas.
the Pythagorean identity the cosine double angle formulas 
Angle of Elevation and Depression
Precalculus Basic Trigonometry
How to define an angle of elevation or an angle of depression.
trigonometry angle of elevation angle of depression 
The Cosine Addition Formulas
Precalculus Advanced Trigonometry
How to derive the cosine of a difference formula.
the unit circle the law of cosines the distance formula cosine of a difference formula 
The Sine Addition Formulas
Precalculus Advanced Trigonometry
How to derive the sine of a sum formula.
cosine of a difference formula the cofunction identities the sine of a sum formula 
Radian Measure of Angles
Precalculus Trigonometric Functions
How to measure angles using degrees or radians.
angle degree measure acute angle right angle obtuse angle radian measure 
Using the Sine and Cosine Addition Formulas to Prove Identities
Precalculus Advanced Trigonometry
How to use the sine and cosine addition formulas to prove the cofunction identities.
the cosine addition formulas the sine addition formulas 
Angle Inclination of a Line
Precalculus Advanced Trigonometry
How to find the angle of inclination of a line.
angle inclination horizontal lines tangent slope 
The Angle Between Vectors
Precalculus Vectors and Parametric Equations
How to compute the angle between two vectors.
dot product angle between vectors position vectors 
The Euler Formula
Precalculus Polar Coordinates and Complex Numbers
How to use the Euler Formula to convert a complex number from the exponential form to rectangular form.
complex numbers trigonometric form Euler formula e sine cosine modulus argument 
The Midpoint and Distance Formulas in 3D
Precalculus Vectors and Parametric Equations
How to derive the formula for the midpoint of a segment in three dimensions.
position vectors the vector from point a to point b the midpoint formula vector addition scalar multiplication 
Conic Section Formulas
Precalculus Conic Sections
How to identify a conic section by its formula.
parabola circle ellipse hyperbola center focus 
The Distance Formula in Polar Coordinates
Precalculus Polar Coordinates and Complex Numbers
How to derive the distance formula for polar coordinates.
polar coordinates the law of cosines triangles 
The Angle Between Planes
Precalculus Vectors and Parametric Equations
How to find the angle between planes, and how to determine if two planes are parallel or perpendicular.
normal vector the angle between planes perpendicular planes dot product scalar multiple parallel planes 
Change of Base Formula
Precalculus Exponential and Logarithmic Functions
How to use the change of base formula for logs to evaluate a logarithmic statement.
change of base log logarithm 
Applied Linear Equations: Geometry Problem
Precalculus Linear Equations and Inequalities
How to find the angles of a triangle by creating a linear equation.
word problem angle measure 
The Circle
Precalculus Conic Sections
How to use the distance formula to derive the equation for a circle.
circle center radius distance formula equation for a circle 
The Circle
Precalculus Equations of Lines, Parabolas and Circles
How to use the distance formula to derive the equation for a circle.
circle center radius distance formula equation for a circle 
Evaluating Sine and Cosine at Other Special Angles
Precalculus Trigonometric Functions
How to measure the sine and cosine of 150.
sine cosine unit circle definitions of sine and cosine angles in standard position reference angles