MATH 2A Lecture 1: MATH 2A - Lecture 1 - Four ways to represent a function

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15 Oct 2018

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MATH 2A Lecture 1: MATH 2A - Lecture 1 - Four ways to represent a function

MATH 2A Lecture 2: MATH2A Lecture 2- Exponential Functions and Inverse Functions

MATH 2A Lecture Notes - Lecture 3: Inverse Function, Trigonometric Functions

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Math 2a - lecture 1 - four ways to represent a function. A function f is a rule that assigns to each element x in a set d, exactly one. For each x there is only one f(x) element called f(x) in set e. Remember, it is ok to have the same f(x) for several different values of x, but we can not have several different f(x) for the same x. In general we show functions as f(x), f(t), h(s), or anything else and we read it as f of x . If we have a curve in xy plane, if and only if no vertical line intersects with the curve more than once, than the curve is the graph of a function of x. Functions arise whenever one quantity depends on another. The area of a circle depends on its radius. The cost of mailing an envelope depends on its weight. cost(c) weight(w) c(w)

Related Questions

Using the lâhospitalâs rule so

Solve this one

Sketch using these guidelines

pul aill al thes information together to sketch graphs that reveal the important You might ask: Why don't we just use a graphing calculator or computer to graph a It's true that modern technology is capable of producing very accurate graphs. But K 21+1+2 features of functions curve? Why do we need to use calculus? even the best graphing devices have to be used intelligently. It is easy to arrive at a misleading graph, or to miss important details of a curve, when relying solely on tech- nology. (See "Graphing Calculators and Computers" at www.stewartcalcelus.com, espe 4 discover the most interesting aspects of graphs and in many cases to and minimum points and inflection points exocily instead of approximately cially Examples 1, 3.4, and 5. See also Section 4.6.) The use of calculus enables us to calculate maximum FIGURE 1 For instance, Figure I shows the gr aph of /(x)-è¨-21x, + 18x + 2.At first glance it seems reasonable: It has the same shape as cubic curves like y x and it appears to have no maximum or minimum point. But if you compute the derivative, you will see that there is a maximum when x-0.75 and a minimum when x 1. Indeed if we zoom in to this portion of the graph, we see that behavior exhibited in Pigure 2 Without calculus, we could easily have overlooked it. 6a, FIGURE 2 In the next section we will graph functions by using the interaction between calculus and graphing devices. In this section we draw graphs by first considering the foilowing information. We don't assume that you have a graphing device, but if you do have one you should use it as a check on your work. â Guidelines for Sketching a Curve every item is relevant to every function. (For instance, a to make a sketch that displays the most important aspects of the function. The following checklist is intended as a guide to sketching a curve y- f(x) by hand. Not given curve might not have an asymptote or possess symmetry.) But the guidelines provide all the information you need A. Domain It's often useful to start by determining the domain D of f, that is, the set B. Intercepts The y-intercept is f(o) and this tells us where the curve intersects the of values of x for which f(x) is defined y-axis. To find the x-intercepts, we set y-0and solve for xã(You can omit this step if the equation is difficult to solve.) ry (a) Even fusction: reflectional symmetry all x in D, that is, the equation of the curve is unchanged when x is replacea by -x, then f is an even function and the curve is symmetric about the y-axis. This means that our work is cut in half. If we know what the curve looks like for 0, then we need only reflect about the y-axis to obtain the com- plete curve [see Figure 3(a). Here are some examples: y-ey-ry x). and for all x in D, then f is an odd function and the curve is symmetric about the origin. Again we can obtain the complete curve if we know what it looks like for x0. [Rotate 180Â° about the origin; see Figure 3(b).] Some b) Oud function rotational symmetry FIGURE 3 simple examples of odd functions are y-xy-x'y - and y-sin

1. Local Versus Absolute Exterema. You might expect from single-variable calculus that if a function has one critical point and critical point is local minimum (say) then that critical point is the global/absolute minimum.

This fails spectacularly in higher dimensions (as there's a famous example of a mistake in a mathematical physics paper because this fact was not properly appreciated). you will compute a simple example in this problem.

Let

(a) Find all critical posints for this function in so doing you will se there is only one

(b) Verify this critical point is a local minimu.

(c) Show that is not absolute minimum be finding values of f(x,y) that are lower than the value at this critical point. We suggest looking at values f(0, y) for suitably chosen y.