Calculus Keep Learning! Yangzhou University Arrangements for the course Teaching hours: 64 hrs (4hrs/wk, 16 weeks) Self-Study hours: 2 times above (8hrs/wk) TA platform: Textbook, extra materials, also for attendance, for submit your homeworks, etc No acceptance for late submission! Zero tolerance for cheating (homeworks, exams) No Scholarship! Keep Learning! Yangzhou University Slide 1 - 2 Study Tips (Good habits) Read before you attend class List three questions you don’t understand Attend the lecture regularly, and taking handwritten notes Do a lot of exercises (including Optionals) “Practice makes perfect” Ask Questions Keep Learning! Yangzhou University Slide 1 - 3 Keep Learning! Yangzhou University The magic of Calculus Sir Isaac Newton: explain the motion of the planets around the sun. Today: Calculus is used in calculating the orbits of satellites and spacecraft, predicting population sizes, estimating how fast oil prices rise or fall, forecasting weather, measuring the cardiac output of the heart, calculating life insurance premiums, and in a great variety of other areas. Keep Learning! Yangzhou University Slide 1 - 5 The beauty of Calculus Calculus is an exciting subject, justly considered to be one of the greatest achievements of the human intellect. I hope you will discover that it is not only useful but also intrinsically beautiful. Keep Learning! Yangzhou University Slide 1 - 6 The extreme brief history of Calculus In this course we will cover the calculus of real functions, which was developed during more than two centuries. The pioneers were Isaac Newton (1642-1737) and Gottfried Wilelm Leibniz (1646-1716). Keep Learning! Yangzhou University Slide 1 - 7 Enter Newton… Isaac Newton (English) is credited with many of the beginnings of calculus. He introduced product rule, chain rule and higher derivatives to solve physics problems. He used calculus to explain many physics problems in his book Principia Mathematica Keep Learning! Yangzhou University Slide 1 - 8 …and Leibniz Gottfried Wilhelm Leibniz (German) systemized the ideas of calculus of infinitesimals. Unlike Newton, Leibniz provided a clear set of rules to manipulate infinitesimals. Leibniz spent time determining appropriate symbols and paid more attention to formality. His work leads to formulas for product and chain rule as well as rules for derivatives and integrals. Keep Learning! Yangzhou University Slide 1 - 9 Newton vs. Leibniz There was much controversy over who (and thus which country) should be credited with calculus since both worked at the same time. Newton derived his results first, but Leibniz published first. Keep Learning! Yangzhou University Slide 1 - 10 Newton vs. Leibniz Today it is known that Newton began his work with derivatives and Leibniz began with integrals. Both arrived at the same conclusions independently. The name of the study was given by Leibniz, Newton called it “the science of fluxions”. Keep Learning! Yangzhou University Slide 1 - 11 Calculus Calculus is a branch of mathematics that has tremendous application and is phenomenally vast. It is essentially covered in two segments namely differential caculus and integral calculus. Keep Learning! Yangzhou University Slide 1 - 12 Differential Fundamental Thm of Calculus Integral Limits Keep Learning! Yangzhou University Slide 1 - 13 Why study calculus Calculus is the study of mathematically defined change. You get a series of mathematical equations that come together to tell you how things change over a period of time. It will introduce you to the basic concepts of mathematics used to study almost any type of changing phenonema with a controlled setting. Studying calculus will develop invaluable scientific sense and practical problem solving skills in you. You will understand how to think logically to reduce a complex system to a few interacting components. Your mind will develop into a powerful systematic instrument. Keep Learning! Yangzhou University Slide 1 - 14 Chapter 1 Functions Keep Learning! Yangzhou University 1.1 Review of Functions Keep Learning! Yangzhou University Figure 1.1 Keep Learning! Yangzhou University Slide 1 - 17 A function is defined by three elements: A domain: The set of numbers which may be '' fed into the machine''. A range: The set of numbers that may be '' emitted by the machine''. A transformation rule: The crucial point is that to every number in its domain corresponds one and only one number in its range. Keep Learning! Yangzhou University Slide 1 - 18 Example 1 Determine if each of the following are functions. 2 y = x +1 (a) 2 (b) y = x + 1 Solution (a) The first one is a function. No matter what values of x you put into the equation, there is only one possible value of y . (b) It is not a function. Choose a value of x , say x = 3 and plug this into the equation. y 2 = 3 + 1 = 4 . Now there are two possible values of y that we could use here. We could use y = 2 or y = −2 . Since there are two possible values of y that we get from a single x this equation is not a function. Keep Learning! Yangzhou University Slide 1 - 19 Graphs We can associate every function a graph. What is a graph? A graph has to be thought of as a subset of the plane. For a function f , we denfine the graph of f to be the set {( x, y ) : x ∈ D, y = f ( x)} Keep Learning! Yangzhou University Slide 1 - 20 Careful!, not all squiggles are functions!, e.g what is f(7) ? The requirement that a function assigns a unique value of the dependent variable to each value in the domain is expressed in the vertical line test The requirement that a function assigns a unique value of the dependent variable to each value in the domain is expressed in the vertical line test Keep Learning! Yangzhou University Slide 1 - 21 Figure 1.2 Keep Learning! Yangzhou University Slide 1 - 22 Keep Learning! Yangzhou University Slide 1 - 23 Figure 1.3 (a) Keep Learning! Yangzhou University Slide 1 - 24 Figure 1.3 (b) Keep Learning! Yangzhou University Slide 1 - 25 Figure 1.3 (c) Keep Learning! Yangzhou University Slide 1 - 26 Figure 1.3 (d) Keep Learning! Yangzhou University Slide 1 - 27 Recall that, the domain of a function is the set of all values that can be plugged into a function and have the function exist and have a real number for a value. So, for the domain we need to avoid division by zero, square roots of negative numbers, logarithms of zero and logarithms of negative numbers, etc. The range of a function is simply the set of all possible values that a function can take. Example 2 Find the domain and range of each of the following functions. (a) f ( x) = x 2 + 1 2 (b) g (t ) = 4 − t (c) h(u ) = Keep Learning! 1 u −1 Yangzhou University Slide 1 - 28 Figure 1.4 domain : (−∞,+∞) range : [1,+∞) Keep Learning! Yangzhou University Slide 1 - 29 Figure 1.5 domain : [−2,2] range : [0,2] Keep Learning! Yangzhou University Slide 1 - 30 Figure 1.6 domain : {u : u ≠ 1} range : {w : w ≠ 0} Keep Learning! Yangzhou University Slide 1 - 31 Composite Functions Functions may be combined using sums ( f + g ) , differences ( f − g ), products ( fg ) , or quotients ( f / g ). The process called composition also produces new functions. In the composition y = f ( g ( x)), f is called the outer function and g is the inner function. Keep Learning! Yangzhou University Slide 1 - 32 Figure 1.8 (a) & (b) Keep Learning! Yangzhou University Slide 1 - 33 1 Example Let f ( x) = 3x 2 − x and g ( x) = , find f(g(x)) and g(f(x)). x 2 3 Example Given f ( x) = x and g ( x) = x − x − 6 , find g f and g g . Keep Learning! Yangzhou University Slide 1 - 34 Keep Learning! Yangzhou University Slide 1 - 35 Figure 1.13 (a) Keep Learning! Yangzhou University Slide 1 - 36 Figure 1.13 (b) Keep Learning! Yangzhou University Slide 1 - 37 Figure 1.13 (c) Keep Learning! Yangzhou University Slide 1 - 38 Keep Learning! Yangzhou University Slide 1 - 39 Identifying symmetry in functions Example Identify the symmetry, if any, in the following functions. (a) f ( x) = x 4 − 2 x 2 − 20 3 (b) g ( x) = x − 3x + 1 (c) h( x) = Keep Learning! 1 x3 − x Yangzhou University Slide 1 - 40 Figure 1.14 Keep Learning! Yangzhou University Slide 1 - 41 Figure 1.15 Keep Learning! Yangzhou University Slide 1 - 42 Figure 1.16 Keep Learning! Yangzhou University Slide 1 - 43 1.2 Representing Functions Keep Learning! Yangzhou University We consider four different approaches to definging and representing functions: formulas graphs tables words Keep Learning! Yangzhou University Slide 1 - 45 Using formulas n n −1 Polynomials: f ( x) = an x + an −1 x + + a1 x + a0 , where the coefficients a0 , a1 , an are real numbers. Rational functions: f ( x) = p( x) / q( x) where p ( x), q ( x)are polynomials Algebraic functions: constructed using the operations of algebras: addition, substraction, multiplication, division and roots. e.g. f ( x) = 2 x 3 + 4 Exponential functions: f ( x) = b x where b ≠ 1 is a positive real number Logarithmic functions: f ( x ) = log b x where b > 0 and b ≠ 1 Trigonometic functions: sin x, cos x, tan x, cot x, sec x, csc x Keep Learning! Yangzhou University Slide 1 - 46 Using formulas Keep Learning! Yangzhou University Slide 1 - 47 Using graphs Figure 1.18 Technology or analytical methods? Keep Learning! Yangzhou University Slide 1 - 48 Linear functions The equation of a line is y = mx + b where the slope m and the y-intercept b are constants. This function has a straight-line graph and is called linear function. Keep Learning! Yangzhou University Slide 1 - 49 Keep Learning! Yangzhou University Slide 1 - 50 Piecewise functions Functions have different definitions on different part of the domain are called piecewise functions. If all of the pieces are linear, the function is piecewise linear. Keep Learning! Yangzhou University Slide 1 - 51 Keep Learning! Yangzhou University Slide 1 - 52 Keep Learning! Yangzhou University Slide 1 - 53 Keep Learning! Yangzhou University Slide 1 - 54 Power functions Power functions are a special case of polynomials where n is a positive integer. f ( x) = x n when n is even, the function values are non-negative and the graph passes through the origin, opening upward. where n is an odd integer, the function has values that are positive when x is positive and negative when x is negative. Keep Learning! Yangzhou University Slide 1 - 55 when n is an even integer Keep Learning! Yangzhou University Slide 1 - 56 when n is odd Keep Learning! Yangzhou University Slide 1 - 57 Root functions Root functions are a special case of algebraic functions. f ( x) = x1/ n where n>1 is a positive integer. when n is even, the domain and range consists of nonnegative numbers. Their graphs begin steeply at at the origin and then flatten out as x increases. when n is odd, the domain and range consists of all real numbers. Keep Learning! Yangzhou University Slide 1 - 58 when n is even Keep Learning! Yangzhou University Slide 1 - 59 when n is odd Keep Learning! Yangzhou University Slide 1 - 60 Rational functions Keep Learning! Yangzhou University Slide 1 - 61 Transformations of functions and graphs There are several ways to transform the graph of a function to produce graphs of new functions. Four transformations are common: shifts in the x- and y-directions scalings in the x- and y-directions Keep Learning! Yangzhou University Slide 1 - 62 Figure 1.37 Keep Learning! Yangzhou University Slide 1 - 63 Figure 1.38 Keep Learning! Yangzhou University Slide 1 - 64 Figure 1.39 Keep Learning! Yangzhou University Slide 1 - 65 Figure 1.40 Keep Learning! Yangzhou University Slide 1 - 66 Figure 1.41 Keep Learning! Yangzhou University Slide 1 - 67 Figure 1.42 Keep Learning! Yangzhou University Slide 1 - 68 f ( x) = x 2 Keep Learning! Yangzhou University Slide 1 - 69 Figure 1.44 Keep Learning! Yangzhou University Slide 1 - 70 Keep Learning! Yangzhou University Slide 1 - 71 Graph 𝑦𝑦 = 𝑥𝑥 2 + 4𝑥𝑥 − 3 Keep Learning! Yangzhou University Slide 1 - 72 1.3 Trigonometric Functions Keep Learning! Yangzhou University Figure 1.45 (a) & (b) Keep Learning! Yangzhou University Slide 1 - 74 Figure 1.46 Keep Learning! Yangzhou University Slide 1 - 75 Figure 1.47 Keep Learning! Yangzhou University Slide 1 - 76 Keep Learning! Yangzhou University Slide 1 - 77 Figure 1.48 Keep Learning! Yangzhou University Slide 1 - 78 Figure 1.49 Keep Learning! Yangzhou University Slide 1 - 79 Figure 1.50 Keep Learning! Yangzhou University Slide 1 - 80 Keep Learning! Yangzhou University Slide 1 - 81 Keep Learning! Yangzhou University Slide 1 - 82 Figure 1.51 (a) & (b) Keep Learning! Yangzhou University Slide 1 - 83 Figure 1.52 (a) & (b) Keep Learning! Yangzhou University Slide 1 - 84 Figure 1.53 Keep Learning! Yangzhou University Slide 1 - 85 Figure 1.54 Keep Learning! Yangzhou University Slide 1 - 86