We review Angles, Polygons, Congruence, and Similarity.
Homework:
#5 – #20 from the 4 pages below:
We review Set Language and Matrices.
A set is a well-defined collection of distinct objects. We talk about how to describe a set, the concept of an element, a subset, when two sets are equal. We also talk about the universal set, the empty set, the complement set for a set, the set union and intersection operations.
We talk about the Venn diagram to represent sets.
We also go over some more practice with matrices.
Homework: From the three pages below: #1 – #5, #11 – #14, #15 – #17
Page 1, Page 2, Page 3, Page 4
Answers to last week’s homework:
We study multiplication of a matrix by a scalar and multiplication of two matrices.
A matrix can be multiplied by a real number (usually called a scalar). If k is a scalar, then the scalar multiplication of a matrix A by k, denoted by kA, is obtained by multiplying every element of A by k.
Matrices multiplication is defined as follows:
If A is a matrix of order m x n and B a matrix of order n x p, then the product AB is a matrix of order m x p whose element at the ith row and jth column is the sum of the products of the corresponding elements in the ith row of A and jth column of B.
If the column number of A is not equal to the row number of B, then AB is undefined.
We introduce Identity Matrix of order n, which has 1 on its major diagonal line and 0 anywhere else..
Homework:
Workbook Page 21, #7, #10 – #12, #18, #19. Please use last lesson’s homework pages for the questions.
Answers to last week’s homework:
We start a new topic today. We study matrices.
In real life, we often use tables to help organize data. If we abstract the concept by extracting the data from a table and arrange them in a rows and columns with brackets, we call this rectangular array of numbers a matrix. The numbers in a matrix are called entries or elements. An element is identified by its row and column positions in the matrix. If a matrix has m rows and n columns, we say that the order of this matrix is m x n. A matrix having the same number of rows and columns is called a square matrix. For a square matrix, we can simply say its order with the number of rows.
We usually use capital letters to represent matrices.
Two matrices A and B are equal, written as A = B, if they have the same order and their corresponding elements are equal.
We then discuss the addition and subtraction of two same-order matrices.
If A and B are two matrices of the same order, then sum A+B is the matrix obtained by adding the corresponding elements in A and B.
Similarly, we define subtraction of two same-order matrices.
We talk about zero matrix where all elements are zero. It is often represented as O.
Homework:
Page 1, Page 2, Page 3, Page 4, Page 5, Page 6, Page 7, Page 8 (please keep these pages, we will need them for the next two lessons)
Workbook Page 19, #1 – #6, #12, #14, #16
We continue study of standard deviation. We first review the formula for ungrouped data and grouped data.
We apply the standard deviation to help analyze two data sets. While means can give us the picture of average, standard deviation helps us to determine how consistent the data are. For example, if we look at two sets of data representing two basketball players’ scores, the lower the standard deviation, the more consistent the player is.
Homework:
Print these pages (they are links, click to download): Page 1, Page 2, Page 3, Page 4
Workbook Page 2, #7, 8, 9, 10, 12, 14, 16.
Answers to the last week’s homework:
We study standard deviation. In statistics, we have learned using mean to find the average, and we have learned to use range and interquartile range to see the spread of the data. But both range and interquartile range are not very good as the tool to represent the spread of the data.
A better way is the measure called standard deviation:
Standard Deviation SD = sqrt(sum of (Xi – AvgX)^2/N)
where N is the total number of data, AvgX is the mean of the data. Xi – AvgX is called the deviation of Xi from the mean AvgX for each i = 1, 2, …, N
For a set of grouped data in the form of a frequency table, we have
Mean AvgX = sum of fx / sum of f
where x is the class mark of each class and f is the frequency of the corresponding class.
Standard Deviation SD = sqrt(sum of f(Xi – AvgX)^2 / sum of f)
[Sorry, I can’t type using the summation notation sigma, which is what we learn in the class. This will simplify the writing.]
Here is a written proof of going from the definition to a formulae often used:
sqrt(∑(Xi – AvgX)^2 / N) = ∑Xi^2 / N – (∑Xi / N)^2
I showed the proof in the classroom, but students may not get it.
Homework (pages are links, click to download):
We continue our study of complex number. Today we talk about representing complex numbers in Complex Plane and how to calculate the magnitude of a complex number. We also look at various properties of a complex number with its conjugate.
Homework (pages are links. Click to download): Page 1, Page 2, Page 3,
3.2.1 – 3.2.7, 3,3.1 – 3.3.1 – 3.3.7
Two events are called to be independent events if the occurrence or non-occurrence of one event does not affect the probability of the other event.
If A and B are independent events, the probability of both events A and B occurring is the product of their individual probabilities:
P(A and B) = P(A) * P(B)
With this, we can simplify tree diagrams when dealing with problems with multiple same items by simply marking their probabilities.
When two (or more) events are dependent to each other, we cannot use the product rule, but we can still use the tree diagrams to help us finding probabilities.
Homework:
Print these pages (pages are links. Click to download): Page 1, Page 2, Page 3
Workbook Page 12, #6 – #10, #16 – #20.
We start on probability. Students should have learned some basic concepts before about simple probability, the concept of a sample space with events consisting of some outcomes. In this chapter ,we study probabilities with multiple stages.
When a random experiment involves two stages, we can use a rectangular grid, called a probability diagram, to represent the sample space to help us find probabilities.
If a random experiment has two or more stages, we can use a tree diagram to represent the process, which should help us see all the possible outcomes and figure out the outcomes associated with a particular event.
We then talk about mutually exclusive events. In a sample space, two events are mutually exclusive if they cannot occur at the same time. If A and B are two mutually exclusive events, the the probability of A or B occurring is: P(A or B) = P(A) + P(B).
Homework:
Print these pages (pages are links. Click to download): Page 1, Page 2
Workbook Page 11, #1 – #5, #21.