MAT-2240 Midterm: MATH 2240 App State Spring2011 Test2 answer key
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February 17th, 2011: (15 points) recall y = a0 + a1x is the least square line for (x1, y1), (x2, y2), . Find the least square line for the data set: ( 2, 1), ( 1, 1), (0, 1), and (1, 1). Putting this all together, we get: (x t x) 1x t y = Answer: the least squares line for this data set is y = (2/5)x + (1/5): (18 points) elementary matrices (a) a = . Fill out the table by describing the elementary operation performed and giving the operation"s corre- sponding elementary matrix. Operation 1 was swap r1 and r3. the corresponding elementary matrix is e1 = . Operation 2 was 2 times r2 added to r3. the corresponding elementary matrix is e2 = . Operation 3 was 3 times r3 added to r1. the corresponding elementary matrix is e3 = . Operation 4 was scale r2 by 1/2. the corresponding elementary matrix is e4 = .
