Cheatography

# Math 140 Exam 1 Cheat Sheet (DRAFT) by AudrieL.

Formula Sheet for exam

This is a draft cheat sheet. It is a work in progress and is not finished yet.

### Matrices

 Matrix Manipu­­la­tions AT: Transpose of A - Switch Rows with Columns (R1 becomes C1, R2 becomes C2 etc.) -A = -1 . A A-1: Inverse of A A-1 . I = I = A . I Augment Identity matrix to matrix and perform Guass-­­Jordon elimin­­ation on both to get change Identity matrix to the Inverse. EROs: Switch Rows Scale Row (Multiply entire row) Add multiple of different row to another A matrix A is in row echelon form if 1. The nonzero rows in A lie above all zero rows (when there is at least a nonzero row and a zero row). 2. The first nonzero entry in a nonzero row (called a pivot) lies to the right of the pivot in the row immedi­­ately above it 2. The first nonzero entry in a nonzero row (called a pivot) lies to the right of the pivot in the row immedi­­ately above it

### Linear Functions

 Slope-­Int­ercept Formula: y=mx+b Point-­Slope: y-y1=m­(x-x1) Slope Formula: (m)=ri­se/run OR m=(y2-­y1)­/(x­2-x1) Standard Form: Ax + By = C
Note that b is equal to y, the b value is where the line crosses on the y-axis when x is equal to zero

### Systems of Equations

 Break-Even Point: (Fixed cost)/­(Pr­ice­/Unit - Variable cost) Equili­brium Point: Qs = Qd, Supply­=Demand

### Systems of Equations

 Break-Even Point: (Fixed cost)/­(Pr­ice­/Unit - Variable cost) Equili­brium Point: Qs = Qd, Supply­=Demand