Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 College: Engineering Campus: Bambang DEGREE PROGRAM BSEE II SPECIALIZATION Electrical YEAR LEVEL 2nd Year COURSE NO. COURSE TITLE TIME FRAME ELCE03 ENGINEERING MATHEMATICS FOR EE 6 hours WK NO. 1 IM NO. I. UNIT TITLE/CHAPTER TITLE Complex Algebra II. LESSON CONTENT 1. Complex Number 2. Operations of Complex Numbers 3. Modulus 4. Axiomatic Foundations 5. Graphical Representation of Complex Numbers 6. Forms of Complex Numbers III. LESSON OVERVIEW This lesson is an introduction to the complex number system and the algebra of complex numbers. IV. DESIRED LEARNING OUTCOMES At the end of the lesson, the students should be able to: 1. 2. 3. 4. V. define an imaginary number; a complex number; distinguish the difference between a real number, an imaginary number, and a complex number; convert complex numbers from one form to another; and, perform complex algebra. LESSON CONTENT REAL NUMBER SYSTEM The real number system consists of: β Natural Numbers (or counting numbers) – these are positive integers such as 1, 2, 3, 4, 5, … β Negative Integers & Zero (i.e., …, -5, -4, -3, -2, -1, 0) β Rational Numbers (or fractions) – these are numbers that can not be reduced to a whole number (i.e., 2/3, ¾, 6/13) β Irrational Numbers (i.e., √2, π, π) GRAPHICAL REPRESENTATION - origin: point corresponding to zero negative: all numbers to the left of zero positive: all numbers to the right of zero COMPLEX NUMBER SYSTEM - Origin: A mathematician wondered what the roots to π₯ 2 + 1 = 0 are. - This gave birth to the imaginary number π = √−1. βͺ βͺ βͺ 2 where π 2 = (√−1) = −1 π 3 = π 2 ⋅ π = (−1) ⋅ π = −π π 4 = (π 2 )2 = (−1)2 = +1 Page |1 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 - In general, for π π , divide π by 4 and determine its remainder… βͺ if remainder is 0, π π = +1 βͺ if remainder is 1, π π = π βͺ if remainder is 2, π π = −1 βͺ if remainder is 3, π π = −π Example 1.1 Evaluate π 385 . Solution: π π = π 385 π = 385 π 385 = = 96 r. 1 4 4 ∴ π 385 = π 4(96) ⋅ π1 = (+1)96 ⋅ π = π OPERATIONS OF COMPLEX NUMBERS ADDITION If π§1 = π + ππ and π§2 = π + ππ, the sum π§1 + π§2 = (π + π) + (π + π)π (3 (−7 Example 1.2 + 2π) + − π) Solution: Simply add the real parts 3 and −7, and then add the imaginary parts 2 and −1, separately as if the imaginary number π is a variable. (3 − 7) + (2 − 1)π −π + π SUBTRACTION If π§1 = π + ππ and π§2 = π + ππ, π§1 − π§2 = (π − π) + (π − π)πExample 1.3 (8 − 6π) − (2π − 7) Solution: Just like in addition, perform the subtraction of the two given complex numbers as if the imaginary number π is a variable. (8 + 7) + (−6 − 2)π ππ − ππ MULTIPLICATION If π§1 = π + ππ and π§2 = π + ππ, π§1 ⋅ π§2 = (π + ππ) ⋅ (π + ππ) = (ππ) + (πππ) + (πππ) + (πππ 2 ) = ππ + πππ + πππ + ππ(−1) = (ππ − ππ) + (ππ + ππ)π Example 1.4 (2 − 3π)(4 + 2π) Solution: (2 − 3π)(4 + 2π) = (2)(4) + (2)(2)π + (−3)(4)π + (−3)(2)(π 2 ) = 8 + 4π − 12π − 6(−1) = (8 + 6) + (4 − 12)π = ππ − ππ DIVISION If π§1 = π + ππ and π§2 = π + ππ, π§1 (π + ππ) = π§2 (π + ππ) π + ππ π − ππ = ⋅ π + ππ π − ππ Page |2 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 (ππ) − (ππ)π + (ππ)π − (ππ)π 2 = (π)2 − (ππ)π + (ππ)π − (π)2 π 2 ππ − πππ + πππ − ππ(−1) = π 2 − π 2 (−1) (ππ + ππ) + (ππ − ππ)π = π2 + π2 NOTE: π − ππ is the complex conjugate of π§2 = π + ππ. (π§Μ 2 = Μ Μ Μ Μ Μ Μ Μ Μ π + ππ = π − ππ) REMARKS: To get the complex conjugate of any complex number, simply change the sign of the imaginary part from positive to negative, or vise versa. Example 1.5 (3 − 2π)/(−1 + π) Solution: 3 − 2π 3 − 2π −1 − π = ⋅ −1 + π −1 + π −1 − π (3)(−1) + (3)(−π) + (−2π)(−1) + (−2π)(−π) = (−1)(−1) + (−1)(−π) + (π)(−1) + (π)(−π) −3 − 3π + 2π + 2π 2 = 1 + π − π − π2 −3 − 3π + 2π + 2(−1) = 1 − (−1) (−3 − 2) + (−3 + 2)π = 2 −5 − π = 2 −π π = − π π π ABSOLUTE VALUE The absolute value or modulus of a complex number π + ππ is defined as |π + ππ| = √π2 + π 2 . Example 1.6 Evaluate |3 + 4π|. Solution: |3 + 4π| = √32 + 42 = √25 = π If π§1, π§2 , π§3 , …, π§π are complex numbers, the following properties hold. |π§1 π§2 … π§π | = |π§1 | |π§2 | … |π§π | 1) |π§1 π§2 | = |π§1 | |π§2 | or π§ |π§ | π§2 2 2) | 1 | = |π§1 | if π§2 ≠ 0 3) |π§1 + π§2 | ≤ |π§1 | + |π§2 | 4) |π§1 + π§2 | ≥ |π§1 | − |π§2 | or and |π§1 + π§2 + β― + π§π | ≤ |π§1 | + |π§2 | + β― + |π§π | |π§1 − π§2 | ≥ |π§1 | − |π§2 | AXIOMATIC FOUNDATIONS OF THE COMPLEX NUMBER SYSTEM Let π§1 = π + ππ, π§2 = π + ππ, π§3 = π + ππ belong to a set π of complex numbers. 1. Equality π + ππ = π + ππ if and only if π = π & π = π 2. Closure Law π§1 + π§2 & π§1 π§2 belong to π 3. Commutative Law of Addition π§1 + π§2 = π§2 + π§1 4. Associative Law of Addition π§1 + (π§2 + π§3 ) = (π§1 + π§2 ) + π§3 5. Commutative Law of Multiplication π§1 π§2 = π§2 π§1 6. Associative Law of Multiplication π§1 (π§2 π§3 ) = (π§1 π§2 )π§3 7. Distributive Law π§1 (π§2 + π§3 ) = π§1 π§2 + π§1 π§3 8a. Additive Identity π§1 + 0 = 0 + π§1 = π§1 (NOTE: 0 is called the identity with respect to addition.) 8b. Multiplicative Identity 1 ⋅ π§1 = π§1 ⋅ 1 = π§1 (NOTE: 1 is called the identity with respect to multiplication.) 9. Additive Inverse For any complex number π§1 there is a unique number π§ in π such that π§ + π§1 = 0; π§ is called the inverse of π§1 with respect to addition and is denoted by −π§1. Page |3 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 10. Multiplicative Inverse For any π§1 ≠ 0 there is a unique number π§ in π such that π§1 π§ = π§π§1 = 1; π§ is called the inverse of π§1 with respect to multiplication and is denoted by π§1−1 or 1/π§1 . GRAPHICAL REPRESENTATION OF COMPLEX NUMBERS If real scales are chosen on two mutually perpendicular axes π′ ππ and π ′ ππ (called the π₯ and π¦ axes respectively) as shown in the figure, we can locate any point in the plane determined by these lines by the ordered pair of real numbers (π₯, π¦) called rectangular coordinates of the point. Examples of the location of such points indicated by π, π, π , π and π in the figure. Since a complex number π₯ + ππ¦ can be considered as an ordered pair of real numbers, we can represent such numbers by points in an π₯π¦ plane called the complex plane or Argand diagram. The complex number represented by π, for example, could then be read as either (3,4) or 3 + 4π. To each complex number there corresponds one and only one point in the plane, and conversely to each point in the plane there corresponds one and only one complex number. Because of this we often refer to the complex number π§ as the point π§. Sometimes we refer to the π₯ and π¦ axes as the real and imaginary axes respectively and to the complex plane as the π§ plane. The distance between two points π§1 = π₯1 + ππ¦1 , and π§2 = π₯2 + ππ¦2 in the complex plane is given by |π§1 − π§2 | = √(π₯1 − π₯2 )2 + (π¦1 − π¦2 )2 . FORMS OF COMPLEX NUMBERS β Rectangular Form: π§ = π + ππ β Polar Form: π§ = π∠π π β Exponential Form: π§ = ππ ππ β Trigonometric Form: π§ = π cis π = π(cos π + π sin π) RECTANGULAR FORM π§ = π + ππ POLAR FORM Page |4 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 π§ = π∠π Conversion from Rectangular to Polar Conversion from Polar to Rectangular π = √π 2 + π 2 π π = tan−1 π π = π cos π π = π sin π EXPONENTIAL FORM π§ = ππ ππ π TRIGONOMETRIC FORM π§ = π cis π = π(cos π + π sin π) NOTE: = cos π + π sin π is known as Euler’s Formula. Example 1.7 Convert each of the given complex numbers into their three other forms: 1.7.1 π§ = 3 + 2π 1.7.2 π§ = −3π 1.7.3 π§ = 6 cis 240° 1.7.4 π§ = 2π −ππ/4 π ππ Solution: 1.7.1 π§ = 3 + 2π The complex number π§ = 3 + 2π is given in rectangular form as π§ = π + ππ = 3 + 2π where π = 3 and π = 2. Since π and π are both positive, as shown the angle π is found on the first quadrant of the complex plane (or Argand diagram) and is found as π 2 π = tan−1 = tan−1 = ππ. ππ° π 3 The vector sum of π and π (or the hypotenuse of the right triangle formed together with π and π) is found as π = √π2 + π 2 = √32 + 22 = √9 + 4 = √ππ Therefore, the polar form of π§ = 3 + 2π is π§ = π∠π = √ππ∠ππ. ππ° Page |5 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 For the exponential form of a complex number, take note of π π . This means that the angle affixed to the imaginary number must be in radians. We must therefore convert the angle π from degrees to radians, and this can easily be achieved by simply multiplying the degreeπ angle by . Thus, the exponential form of π§ = 3 + 2π is 180° π π π(33.69°⋅ π ) 180° = √ππππ.πππππ π§ = ππ ππ = ππ ππ⋅180° = √13π Finally, the trigonometric form of π§ = 3 + 2π is π§ = π cis π = √ππ ππ’π¬ ππ. ππ° 1.7.2 π§ = −3π The complex number π§ = −3π is also given in rectangular form as π§ = π + ππ = −3π where π = 0 and π = −3. Since π (the real part of the complex number) is zero, the complex vector is vertical with direction pointing downwards (negative) as shown. The angle π is measured from the positive R-axis and can be solved as −3 π = tan−1 = 270° 0 (NOTE: Trying this in a scientific calculator will result in “Math ERROR”. This is because the −3 calculator is unable to solve for the part of the equation. But as can be seen from the 0 Argand diagram, the terminal side of the angle has travelled exactly three quadrants from the positive R-axis in counterclockwise direction. Since one quadrant is equivalent to 90°, three quadrants is therefore equivalent to 3 × 90° = 270°.) π can be solved as π = √π2 + π 2 = √02 + (−3)2 = √9 = 3 Therefore, the polar form of π§ = −3π is π§ = π∠π = π∠πππ° Furthermore, the exponential form of π§ = −3π is π π(270°⋅ π ) 180° = πππ ππ /π π§ = ππ ππ = 3π Finally, the trigonometric form of π§ = −3π is π§ = π cis π = π ππ’π¬ πππ° 1.7.3 π§ = 6 cis 240° The complex number π§ = 6 cis 240° is given in trigonometric form as π§ = π cis π = 6 cis 240° where π = 6 and π = 240°. Page |6 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 The polar form of π§ = 6 cis 240° is π§ = π∠π = π∠πππ° The exponential form of π§ = 6 cis 240° is π π(240°⋅ π ) 180° = 6π π 4π/3 π§ = ππ ππ = 6π As for the rectangular form, π and π can be solved as π = π cos π = 6 cos 240° = −3 π = π sin π = 6 sin 240° = −3√3 respectively. Thus, the rectangular form of π§ = 6 cis 240° is π§ = π + ππ = −π − π√π π 1.7.4 π§ = 2π −ππ/4 The complex number π§ = 2π −ππ/4 is given in exponential form as π π§ = ππ ππ = 2π −ππ/4 −π where π = 2 and π π = . 4 (NOTE: The angle π π = −π 4 is measured from the positive R-axis in a clockwise direction, π 4 hence the negative angle. Though this is not incorrect, this is not equivalent to . Positive π π 4 is located on the first quadrant of an Argand diagram while negative is located on the fourth 4 quadrant. Measured in a counterclockwise direction, this angle is equivalent to 7π 7π 180° π π = or π = ⋅ = 315°.) 4 4 π The polar form of π§ = 2π −ππ/4 is π§ = π∠π = π∠πππ° The trigonometric form of π§ = is π§ = π cis π = π ππ’π¬ πππ° And the rectangular form of π§ = 2π −ππ/4 is π§ = π + ππ = (π cos π) + (π sin π)π = (2 cos 315°) + (2 sin 315°)π = √π − √π π 2π −ππ/4 Page |7 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 Page |8 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 VI. LEARNING ACTIVITIES NAME: _____________________________________ COURSE-YR: ________________________ SCORE: _____________________ DATE: _______________________ Activity 1.1 Plot each of the given complex numbers in an Argand diagram and label all the necessary parts. Also, convert each to its three other forms. 1. π§ = −1 + 2π 2. π§ = −√6 − √2 π 3. π§ = 14.7∠45°49′ 4. π§ = −3 cis 310° 5. π§ = 5π ππ Page |9 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 VII. EVALUATION (Note: Not to be included in the student’s copy of the IM) P a g e | 10 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE NAME: _____________________________________ COURSE-YR: ________________________ IM No.: ELCE03-2S-2021-2022 SCORE: _____________________ DATE: _______________________ Quiz 1.1 Given: π§1 = 1 + 2π π§2 = 2 − 3π 1. 2. 3. 4. 5. (10 pts.) (10 pts.) (10 pts.) |3π§1 − 4π§2 | =? π§13 − 3π§12 + 4π§1 − 8 =? Simplify: (15 pts.) (15 pts.) 3π 30 − π19 2π − 1 Convert item 2 into its three other forms. Convert item 3 into its three other forms. P a g e | 11 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 VIII. ASSIGNMENT P a g e | 12 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE NAME: _____________________________________ COURSE-YR: ________________________ IM No.: ELCE03-2S-2021-2022 SCORE: _____________________ DATE: _______________________ Assignment 1.1 Simplify each of the following: 1. (5 + 3π) + {(−1 + 2π) − (7 − 5π)} 2. (8 − 6π) − (−7 − π) 3. (4 + 2π)(2 − 3π)(2 − π) 4. (−1 + 2π){(7 − 5π) + (−3 + 4π)} 5+5π 20 5. + 3−4π 4+3π P a g e | 13 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution” Republic of the Philippines NUEVA VIZCAYA STATE UNIVERSITY Bambang, Nueva Vizcaya INSTRUCTIONAL MODULE IM No.: ELCE03-2S-2021-2022 IX. A) REFERENCES Book/Printed Resource Bird, J. (2020). Higher Engineering Mathematics, 6th Edition. Oxford, UK: Elsevier's Science and Technology Rights Department. Dulay, V. N. (2001). Reviewer/Text in Advanced Engineering Mathematics. Manila: Rex Book Store. Kreszig, E. (2006). Advanced Engineering Mathematics 10th Edition. New York: John Wiley and Sons, Incorporated. Spiegel, M. R. (1965). Schaum"s Outline of Theory and Problems of Laplace Transforms. USA: McGraw Hill, Incorporated. B) ONLINE RESOURCES http://www.soton.ac.uk/~cjg/eng1/modules/modules.html http://www.mit.opencourseware.com P a g e | 14 NVSU-FR-ICD-05-00 (081220) “In accordance with Section 185, Fair Use of a Copyright Work of Republic Act 8293, the copy righted works included in this material may be reproduced for educational purposes only and not for commercial distribution”