Math 9, Lesson 2, Spring 2017, 2/5/2017

Weidong Posted in Homework, Math 9, Spring 2017, Teaching info，
05 February 2017
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We start the new chapter on vectors.

While a scalor is a quantity that has only magnitude, a vector is a quantity that has both magnitude and direction. We usually use directed line segment to represent a vector. The direction of the line segment, indicated by an arrow, represents the direction of the vector, and the length of the line segment represents the magnitude of the vector.

Two vectors are equal if they have equal magnitude and are in the same direction.

For vector additions, we study the triangle law and parallelogram law of vector additions.

Homework:

Page 1, Page 2, Page 3, Page 4

Workbook P 31, #1, #2, #3, #4, #5, #12, #15.

Answers to last week’s homework: Answers

Algebra 2, Lesson 2, Spring 2017, 2/5/2017

Weidong Posted in Algebra 2, Spring 2017, Teaching info，
05 February 2017
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We study circles, ellipses, and hyperbolas.

A circle is a locus of points in a plane that are a fixed distance from a given point in that plane. The fixed distance is the radius of the circle and the given point is the center.

An ellipse is defined geometrically as: for a given two points F1 and F2 in a plane, for any positive constant k greater than the distance F1F2, the locus of all points P in the plane such that PF1 + PF2 = k.

A hyperbola is defined as: for a given two points F1 and F2 in a plane, for any positive contstant k, the locus of all points P in the plane such that |PF1 – PF2| = k.

We study the common properties of these three kinds.

 

Algebra 2, Lesson 1, Spring 2017, 1/29/2017

Weidong Posted in Algebra 2, Spring 2017, Teaching info，
29 January 2017
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This is our first lesson for Algebra 2. Students got their textbooks.

Today We study parabolas, with its relationship to quadratic functions.

Three parents came to the class, with two stayed through the class. I welcome the input from the students and the parents.

Parents: please talk to your kid to get his feedback. Examine your kid’s notebook to see how much exercise he/she did in the class.

We started with talking about the geometric definition of a parabola, its basic properties and how to find the function based on the information about vertex, focus, directrix, etc. We did this by looking at a number of problems. Students then got time to work on some problems. We then talked about those problems and solved them in the class.

After the break, we looked at using parabola to solve problems. Again, we looked a few problems before the students worked on a few more. We then talked about those.

Lastly we looked at one of the major applications of parabola: finding the minimum and maximum values of quadratic functions. Again, we studied a few examples, having students work on a few more. We finished after going over those problems again.

This is a pretty fast paced class and I want to make sure that students feel OK. As I told students, they should have notebooks with them, not just note pad. They should get into a habit of taking notes in the class.

Again, please provide your feedback.

 

Math 9, Lesson 1, Spring 2017, 1/29/2017

Weidong Posted in Homework, Spring 2017, Teaching info，
29 January 2017
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Students will bring home their final exam papers. I have uploaded answers for the exam here.

Apart from going over some exam questions, we review the properties of circles.

In the symmetry properties category, we have the following:

  • Equal chords are  equidistant from the center;
  • The perpendicular bisector of a chord passes through the center;
  • Tangents from an external point are equal in length;
  • The line joining an external point to the center bisects the angle between the tangents

In the category of angle properties, we have:

  • Angle in a semicircle is a right angle;
  • Angle between tangents and radius is a right angle;
  • Angle at the center is twice the angle at the circumference;
  • Angle in the same segment are equal;
  • Angle in opposite segments are supplementary.

Homework:

Page 0, Page 1, Page 2, Page 3

#2, #4, #6, #8, #10, #12, #14, #16, #18

Math 9, Lesson 16, Fall 2016, 1/22/2017

Weidong Posted in Fall 2016, Teaching info，
22 January 2017
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We have our Fall semester final exam today. I will have the test results ready for students next Sunday.

Next Sunday will be the first class for 2017 Spring semester.

 

Math 9, Lesson 15, Fall 2016, 1/15/2017

Weidong Posted in Fall 2016, Teaching info，
15 January 2017
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We review what we have learned this semester in preparation for the final exam for next Sunday.

In this semester so far we have learned matrix and matrix multiplications, along with going over old content of equations, inequalities, set languages, angles, polygons, congruence, and similarities.

We will have the final exam next Sunday 1/22/2017.

There is no specific homework today. Students should go over their past homework questions.

Answers for last week’s homework: Answers

Math 9, Lesson 14, Fall 2016, 1/8/2017

Weidong Posted in Fall 2016, Homework, Teaching info，
08 January 2017
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We review Angles, Polygons, Congruence, and Similarity.

Homework:

#5 – #20 from the 4 pages below:

Page1, Page2, Page3, Page4

Answers to last lesson’s homework: Answer1

Math 9, Lesson 13, Fall Semester, 12/18/2016

Weidong Posted in Fall 2016, Homework, Teaching info，
18 December 2016
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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 page2 below: #1 – #5, #11 – #14, #15 – #17

Page 1, Page 2, Page 3, Page 4

Answers to last week’s homework: Please see Lesson 11’s answer pages.

 

Math 9, Lesson 12, Fall 2016, 12/11/2016

Weidong Posted in Fall 2016, Homework, Teaching info，
11 December 2016
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We spend more time on matrix multiplication by doing more practice questions.

Homework:

Workbook Page 23, #14 – #16, #20, #22 – #24. Please use Lesson 10’s homework pages for the questions.

Answers to last week’s homework: Please see Lesson 11’s answer pages.

 

Math 9, Lesson 11, Fall 2016, 12/04/2016

Weidong Posted in Teaching info，
03 December 2016
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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: Answers1  Answers2

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