cosine of a difference formula 47 videos

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 
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 
The DoubleAngle Formulas
Precalculus Advanced Trigonometry
How to use the sine and cosine addition formulas to prove the doubleangle formulas.
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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 
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 
The Law of Cosines
Precalculus Basic Trigonometry
How to define and use the law of cosines.
law of cosines ratios triangles 
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 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 
Computing Difference Quotients
Precalculus Introduction to Functions
How to compute and simplify the difference quotient of a linear function.
functions function notation slope secant line difference quotient 
Computing Difference Quotients
Precalculus Equations of Lines, Parabolas and Circles
How to compute and simplify the difference quotient of a linear function.
functions function notation slope secant line difference quotient 
The Definitions of Sine and Cosine
Precalculus Trigonometric Functions
How we define sine and cosine for all angle measures using the unit circle.
sine cosine right triangle definitions of sine and cosine angles in standard position unit circle definitions of sine and cosine 
The Inverse Cosine Function
Precalculus Advanced Trigonometry
How to restrict the domain of cosine so it will have an inverse function.
inverse functions one to one inverse cosine arccosine 
Find an Equation for the Sine or Cosine Wave
Precalculus Trigonometric Functions
How to identify the graph of a stretched cosine curve.
sine cosine period amplitude intercepts turning points 
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 
Evaluating Sine and Cosine at Special Acute Angles
Precalculus Trigonometric Functions
How do we measure sine and cosine of pi/4?
sine cosine unit circle definitions of sine and cosine angles in standard position 
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 
Trigonometric Ratios: Cosine
Precalculus Basic Trigonometry
How to define the cosine ratio and identify the cosine of an angle in a right triangle.
trigonometry ratio right triangle sine SOH CAH TOA 
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 
Conic Section Formulas
Precalculus Conic Sections
How to identify a conic section by its formula.
parabola circle ellipse hyperbola center focus 
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