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Chapter 1 Solutions
Developmental Mathematics (9th Edition)
- 1. Matrix Operations Given: A = [ 33 ]A-[3-321] -3 B = [342]B-[3-41-2] (a) A² A2 Multiply A× A: -3 = (3 x 32x-3) (3 x 22 x 1) | = |[19–63 |-9-3 -6+21] = A² = 33 33 1-3×3+1x-3) (-3×2+1x1) [12]A2=[3-321][3-321]=[(3×3+2x-3)(-3×3+1x-3)(3×2+2×1)(-3×2+1×1)]=[9-6-9-36+2-6+1 ]=[3-128-5] (b) | A ||A| Determinant of A | A | (3 × 1) (2 x-3)=3+ 6 = 9|A|=(3×1)-(2x-3)=3+6=9 (c) Adjoint of A Swap diagonal elements and change sign of off-diagonals: A = [33], so adj (A) = |¯²]A=[3-321], so adj(A)=[13–23] -3 (d) B-¹B-1 First find | B ||B|: |B | (3x-2)- (1 × -4) = -6 + 4 = −2|B|=(3x-2)-(1x-4)=-6+4=-2 Then the adjoint of B: adj (B) = [² 3 adj(B)=[-24-13] Now, B-1 1 = |B| · adj (B) = 1 [²¯¯³¹³] = [2₂ B 0.5 |B-1=|B|1-adj(B)=-21[-24-13]=[1-20.5-1.5] 2. (a) Matrix Method: Solve (2x + 3y = 6 (2x-3y=14 {2x+3y=62x-3y=14 Matrix form: 22 33-22 = [223-3][xy]=[614] Find inverse of coefficient matrix: Determinant: | M | (2x-3) - (3 x 2) = -6 -6 = -12|M|=(2x-3)-(3×2)=-6-6=-12 Adjoint: adj(M) = [3]adj(M)-[-3-2-32] So…arrow_forwardLet the region R be the area enclosed by the function f(x)= = 3x² and g(x) = 4x. If the region R is the base of a solid such that each cross section perpendicular to the x-axis is an isosceles right triangle with a leg in the region R, find the volume of the solid. You may use a calculator and round to the nearest thousandth. y 11 10 9 00 8 7 9 5 4 3 2 1 -1 -1 x 1 2arrow_forwardUsing the accompanying Accounting Professionals data to answer the following questions. a. Find and interpret a 90% confidence interval for the mean years of service. b. Find and interpret a 90% confidence interval for the proportion of employees who have a graduate degree. view the Accounting Professionals data. Employee Years of Service Graduate Degree?1 26 Y2 8 N3 10 N4 6 N5 23 N6 5 N7 8 Y8 5 N9 26 N10 14 Y11 10 N12 8 Y13 7 Y14 27 N15 16 Y16 17 N17 21 N18 9 Y19 9 N20 9 N Question content area bottom Part 1 a. A 90% confidence interval for the mean years of service is (Use ascending order. Round to two decimal places as needed.)arrow_forward
- Let the region R be the area enclosed by the function f(x) = ex — 1, the horizontal line y = -4 and the vertical lines x = 0 and x = 3. Find the volume of the solid generated when the region R is revolved about the line y = -4. You may use a calculator and round to the nearest thousandth. 20 15 10 5 y I I I | I + -1.5 -1 -0.5 0.5 1 1.5 2 2.5 3 -5 I -10 -15 I + I I T I I + -20 I + -25 I I I -30 I 3.5 4 xarrow_forwardThe joint probability function for the random variables X and Y is y 0 1 2 P(X, Y) = x0 [3/28 9/28 3/281 = 13/14 3/14 2 1/28 0 0 0 Find Mx, My, E(XY), OXY.arrow_forwardIf, based on a sample size of 900,a political candidate finds that 509people would vote for him in a two-person race, what is the 95%confidence interval for his expected proportion of the vote? Would he be confident of winning based on this poll? Question content area bottom Part 1 A 9595% confidence interval for his expected proportion of the vote is (Use ascending order. Round to four decimal places as needed.)arrow_forward
- P(x, y) = {e-(x+y) x≥0, y ≥0 0 otherwise find x, y, x,y JX, 4 буarrow_forwardThe joint density function of two continuous random variables X and Y is: p(x, y) = {Kcos(x- Find (i) the constant K + y) 0 0arrow_forwardplease show all the workarrow_forwardA random variable X has a Gaussian distribution. The mean value of X is 2 and the variance is 4 volts. Compute the following probabilities: a) P(X3) c) P(X<-2) d) P(2arrow_forwardLet X and Y be random variables having joint density function 0≤x≤1,0≤ y ≤ 1 find X, Y, 0, 0, OXY otherwise p(x,y) = {x+yarrow_forwardFind the probability in tossing a fair coin three times, there will appear a) 3 H b)2 H 1T c) 2 T and 1 H d) 3 T.arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_iosRecommended textbooks for you
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