the identity matrix 21 videos

The Identity Matrix
Precalculus Systems of Linear Equations and Matrices
How to determine the identity matrix of order n.
matrices square matrices the identity matrix matrix multiplication 
Trigonometric Identities
Precalculus Trigonometric Functions
How to use the unit circle to derive the tangent identity and the Pythagorean identity.
identities the unit circle trigonometric identities the Pythagorean identity 
Solving Linear Systems Using Matrix Algebra
Precalculus Systems of Linear Equations and Matrices
How to convert a system of linear equations into a matrix equation and solve it.
matrices square matrices matrix equation coefficient matrix inverse matrix identity matrix matrix multiplication 
The Inverse of a Square Matrix
Precalculus Systems of Linear Equations and Matrices
How to determine whether two matrices are inverses.
matrices square matrices the identity matrix matrix multiplication invertible inverse matrix 
Using Trigonometric Identities
Precalculus Trigonometric Functions
How to simplify a trigonometric expression by converting to sines and cosines and using algebra.
reciprocal identities 
The Reciprocal Trigonometric Functions
Precalculus Trigonometric Functions
How to define the reciprocal trigonometric functions, the reciprocal identities, and the Pythagorean identities.
identities the unit circle reciprocal identities the Pythagorean identities 
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 
Graphing the Reciprocal Trigonometric Functions
Precalculus Trigonometric Functions
How to use the unit circle to derive identities that are useful in graphing the reciprocal trigonometric functions.
identities the unit circle the cofunction identities the "add Π@" identities 
Invertible Square Matrices and Determinants
Precalculus Systems of Linear Equations and Matrices
How to determine whether a square matrix is invertible using its determinant.
square matrices invertible determinant zero determinant inverse of a 2x2 matrix 
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 
2x2 Determinants
Precalculus Systems of Linear Equations and Matrices
How to compute the determinant of a 2x2 square matrix.
square matrices determinant 2x2 determinant 
Asymptotes of Secant, Cosecant, and Cotangent
Precalculus Trigonometric Functions
How to find the vertical asymptotes of secant, cosecant, and cotangent.
reciprocal identities vertical asymptotes 
Square Matrices
Precalculus Systems of Linear Equations and Matrices
How to determine whether two matrices can be multiplied, and if so, what the dimensions of the product will be.
matrices rows columns dimension matrix multiplication 
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 
Cramer's Rule
Precalculus Systems of Linear Equations and Matrices
How to solve a system of two linear equations with two unknowns using Cramer's rule.
systems of linear equations Cramer's rule determinant coefficient matrix 
Transforming the Tangent Graph
Precalculus Trigonometric Functions
How to graph y = tan(q) for one or more periods.
sine cosine tangent opposite angle identities intercepts asymptotes periodicity period 
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 
Properties of Logarithms
Precalculus Exponential and Logarithmic Functions
How to evaluate logarithms when the argument is a recognizable power of the base.
logarithmic functions exponential functions inverse functions identities the common logarithm 
3x3 Determinants
Precalculus Systems of Linear Equations and Matrices
How to compute the determinant of a 3x3 square matrix using minors by expanding along the top row.
square matrices determinant 3x3 determinant minor of an element 
Transforming the Cotangent Graph
Precalculus Trigonometric Functions
How graph the cotangent function using five key points.
cosine sine cotangent even and odd functions the add pi identities period vertical asymptotes