Answers to Lesson 13 Homework

Weidong Posted in Teaching info
Comments Off on Answers to Lesson 13 Homework

3.2.1 Draw your own diagram

3.2.2 a. 25 b. 4 c. 5

3.2.3 63

3.2.4 25

3.2.5 Z1 = a + bi, Z2 = c + di, mid point is (a+c)/2 + (b+d)i/2 = (Z1 + Z2) / 2

3.2.6 a. 1 b. 1 c. 1

3.2.7 2 – i

Math 9, Lesson 13, 12/22/2022

Weidong Posted in Fall 2022, Homework, Math 9, Teaching info
Comments Off on Math 9, Lesson 13, 12/22/2022

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.

Homework (pages are links. Click to download): Page 1Page 2

3.2.1 – 3.2.7

Answers to Lesson 12 Homework

Weidong Posted in Teaching info
Comments Off on Answers to Lesson 12 Homework

3.1.1 z = +/- sqrt(3) i

3.1.2 a. -9 + 9i b. 56 + 33i c. 4 + 36i d. 112/169

3.1.3 a. 7 b. 3/34 + 5i/34

3.1.4 a. 0 b. 0 c. 8 + 4i

3.1.5 -i/2

3.1.6 a. 6 + 3i b. 14/123 + i/41 c. 74/25 – 18i/25

3.1.7 2, 0, -2

Math 9, Lesson 12, 12/15/2022

Weidong Posted in Fall 2022, Homework, Math 9, Teaching info
Comments Off on Math 9, Lesson 12, 12/15/2022

In the next thtree lessons, we study complex numbers.

Today we talk about the arithmetic of complex numbers, addition, subtraction, multiplication and division.

Homework (pages are links, click to download): Page 1Page 2,

3.1.1 – 3.1.7

Answers to Lesson 11 Homework

Weidong Posted in Teaching info
Comments Off on Answers to Lesson 11 Homework

Answers to last week’s homework:

Answers page1, answers page2

Math 9, Lesson 11, 12/8/2022

Weidong Posted in Fall 2022, Homework, Math 9, Teaching info
Comments Off on Math 9, Lesson 11, 12/8/2022

We continue our study on matrix multiplication, as this is something not intuitive for students.

For the resulting matrix’s element at i-th row and j-th column, think of it as the product of the i-th row from the 1st matrix with the j-th column from the 2nd matrix.

Then what is the product of a row and a column? First of all,t they need to have the same number of elements in that row and the column. Then it is the sum of the products of the corresponding elements from the row and the column. That is, you multiple the 1st element from the i-th row to the 1st element from the j-th column, Then the 2nd, etc. Then you add all the products together.

Homework (see Pages from Lesson 9):

Workbook Page 24, #18 – #21.

Answers to Lesson 10 Homework

Weidong Posted in Teaching info
Comments Off on Answers to Lesson 10 Homework

Answers to last week’s homework:

Answers page1, answers page2

Math 9, Lesson 10, 12/1/2022

Weidong Posted in Fall 2022, Homework, Math 9, Teaching info
Comments Off on Math 9, Lesson 10, 12/1/2022

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 i-h row and j-th column is the sum of the products of the corresponding elements in the i-th row of A and j-th 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 (see Pages from Lesson 9):

Workbook Page 21, #7, #10 – #12. Please use last lesson’s homework pages for the questions.