Chapter 5.02 Integrals Feel free to use Wolfram Alpha to help on some of the algebra. For example, you can type sum i=1 to n of (3+i*2/n)^2 * 2/n 2 12 14 16 WEP 18 22 27 28 WEP ------------Part II starts here---------- 34 40 QA: Pick one of the following functions: sin(3x)*sin(2x) cos(3x)*sin(2x) cos(3x)*sin(1x) cos(3x)*cos(2x) cos(3x)*cos(1x) Find the integral of that function from x=-pi to pi hint : graph & use symmetry. These integrals are related to "Fourier Analysis", which is at the heart of various technologies that you might like, such as: DVDs, mp3s, cell phones, WiFi, and even old fashioned AM and FM radio. 41 WEP 44 WEP 48 52 56 60 QB (WEP): i) Do all 3 of the functions in Question A. What do you notice about all of them? Then try sin(3x)*sin(1x) ; do you get the same answer as in Question A? ii) Now try sin(1x)*sin(1x) or sin(2x)*sin(2x); How is the result different? Can you estimate the value using a different kind of symmetry? Can you generalize to other constants (3, 4, 5, ...) ? iii) Now try cos(1x)*cos(1x) or cos(2x)*cos(2x); what can you say now? iv) Now try sin(0x)*sin(0x) and cos(0x)*cos(0x); what slightly weird thing happened? v) Overall, fill in the blanks: if m and n are integers that are >= 0, * the integral of sin(m*x)*sin(n*x) from -pi to pi is __ if m=n, and is __ otherwise. * the integral of cos(m*x)*cos(n*x) from -pi to pi is __ if m=n, and is __ otherwise. * the integral of sin(m*x)*cos(n*x) from -pi to pi is __ if m=n, and is __ otherwise.