pracexam2sol 17C

pracexam2sol 17C - Math 17C (Spring 2007) Kouba Exam 2 Your...

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Unformatted text preview: Math 17C (Spring 2007) Kouba Exam 2 Your Exam ID Number __________ __ 1. PLEASE DO NOT TURN THIS PAGE UNTIL TOLD TO DO SO. 2. IT IS A VIOLATION OF THE UNIVERSITY HONOR CODE TO, IN ANY WAY, ASSIST ANOTHER PERSON IN THE COMPLETION OF THIS EXAM. IT IS A VIOLATION OF THE UNIVERSITY HONOR CODE TO COPY ANSWERS FROM ANOTHER STUDENT’S EXAM. IT IS A VIOLATION OF THE UNIVERSITY HONOR CODE TO HAVE ANOTHER STUDENT TAKE YOUR EXAM FOR YOU. PLEASE KEEP YOUR OWN WORK COVERED UP AS MUCH AS POSSIBLE DURING THE EXAM SO THAT OTHERS WILL NOT BE TEMPTED OR DISTRACTED. THANK YOU FOR YOUR COOPERATION. 2. No notes, books, or classmates may be used as resources for this exam. YOU MAY USE A CALCULATOR ON THIS EXAM. 3. Read directions to each problem carefully. Show all work for full credit. In most cases, a correct answer with no supporting work will NOT receive full credit. What you write down and how you write it are the most important means of your getting a good score on this exam. Neatness and organization are also important. 4. Make sure that you have 7 pages, including the cover page. 5. You will be graded on proper use of limit, derivative, and integral notation. 6. You have until 9:50 am. sharp to finish the exam. 2 1.) (10 pts.) Find the Jacobi Matrix Df(;L‘,y) for fix,” 2 (Si:?:y)) . Y" Y’” X-R mam): Q Ye Ymng) x mew) 2.) (7 pts) How many distinct 9-letter permutations are there of the letters in the word POPPYSEED? a, w) 3 pk} 2E’5 41. q! ___'_s—- a Mo gay "5/02 3.) (7 pts) A group of 13 people includes 7 men and 6 women. In how many ways can a committee of 5 people be chosen if the committee must have exactly 3 women and 2 men? C(63). (10,2/ ; 710- cu : qzo W M W M 4.) (7 pts) You are going to buy 16 freshly-made doughnuts at Krispy Kreme. If you pick from among vanilla, chocolate, maple, raspberry, and glazed doughnuts, in how many ways can you make your selection ? M L! -‘ m,qu 010 M CCAOJLJ): 3 .L X: 5.) (10 pts.) (Drug dissipation) A single dose of zolpidem (a drug for short-term treatment of insomnia) is administered to a patient. A laboratory measurement shows that the patient’s body tissue retains 2.5 mg. of the drug after 6 hours. Let x1 and :32 be the mg. of zolpidem in the person’s body tissue and urinary tract, resp., at time t hours and assume diL'l that E = ——0.2312:1. Use the mathematical model from class to determine formulas for 221 and 2:2. Determine the initial dosage (in mg.) of zolpidem. %:_O.a3lx, J X,C0):L—-ME<(. 455:: +o_a3lx, XRLOJCO /‘ W X1+XalL5 M ) AX: :S”0.231d~>i* “Aid/HQ 1’0-23/‘E-l—c % MY. ’0.l3/‘6’ t _0.9~3/~€_ C 3 C I C C ': C, a -——-—5 ~0.23/~6 ~/ ~o.l3({- X,:ce, (Vb—«9 X,Co):L A CzL —» X,_Le j ’ ~o.23IC‘o/ M >903); 2.5M? ~+ (2.5: L e w.» L: Q-5)e°'23166)z 10 A M ~0.9.3(~e “6 43’f X‘: (03, 044,12 Kat: (0—106, 6.) (Lotka—Voltera Predator-Prey Model) (10 pts.) Consider the system of differential equations given below, where N (t) is the prey population at time t and P(t) is the predator population at time t. Separate variables and integrate to get an implicit solution (in N and P) for this system. A p ) / N-§ %=4N—PN=~<q-P2 elk—3% £57 r dP A . —— N ’4— 7E=PN—5P: MAI—5) “ u 2 q-p ,____.— P am; Sflfi—WN “r 3[%~17M:5[‘~~iidN ~—>r qflxnp~|0: N~ 5M/V-é—Q, 7.) (12 pts.) Consider the two tanks containing water and salt mixtures and connected as shown in the diagram. Tank 1 holds 200 gallons of mixture. Tank 2 holds 250 gallons of mixture. Let 3:1 and x2 represent the pounds of salt in Tank 1 and Tank 2, resp., at time t. Initially, Tank 1 contains 45 pounds of salt and Tank 2 contains 30 pounds of salt. The mixture in each tank is kept uniform by stirring, and the mixtures are pumped from each tank to the other at the rates indicated in the figure. In addition, a mixture containing 2/3 pound of salt per gallon is pumped into Tank 1 at 5 gal./min.; a mixture containing 1/4 pound of salt per gallon is pumped into Tank 2 at 3 gal. /min.; the mixture leaves Tank 2 at 9 gal. / min. SET UP, BUT DO NOT SOLVE, a sytem of differential equations with initial conditions, which represents the amount of salt in each tank. PAY CLOSE ATTENTION TO FLOW RATES IN AND OUT OF EACH TANK l!!! g-lb'éal. 7" Abéql a ggai/min. a 3 gal/m5". it: ; (ram/212v flamed] M ~ (41%. 3M. 47(4004'2’7/‘3. M. M. u». M. -(M: ifi‘ M; X; _ a‘z‘é . “6‘2‘6‘70’Q ~ M . 8.) (7 pts.) A bag holds 7 red, 10 blue, and 6 white basketballs. In how many ways can you select 8 balls, if you must choose at least 1 white ball ? AH» (MM/Me) .~_ QQ3J5’] ~ c033] : 4&7 004 9.) (12 pts.) (Graphical Method) Consider the given graph of zero isoclines with equi- librium (a, b). Use the isocline—hopping method to complete the Sign chart for f1 and f2. Use your results to create a signed Jacobi Matrix and determine if the the equilibrium is stable or unstable. W: we. we New 2. 4; W m can 6)) Mata/'4» We). 10.) Consider the following nonlinear system of differential equations. dxl 2 2 E = x1 - $2 a.) ( 4 pts.) Determine all quilibria gor this system. dmz X17; x310 ——- XI CIXA AND XJ<XA~5</:o —d-t— : 131132 — 2:131 __-., X305"? ngg 1% C010; (2/2; 6-2/ 27% W b.) (14 pts.) For each equilibrium use the analytical approach (Jacobi Matrix and eigenvalues) to determine stability and classify it, or conclude that this method is incon- elusive. DHXVXA) 2 [x2 x, —- 2a] 23'7‘ X! a.) 0129,02: 2]: Ag Mka “fiifil Via : A":o —>> Azo CINCONCLmslvgjj, -—v ~. W “W 1 l“ ’3 M -~ M(A~A:2=M[“2*;3 O The following EXTRA CREDIT PROBLEM is worth 10 points. This problem is OP- TIONAL. 1.) Determine the number of distinct 4-letter permutations that can be made from the letters in the word ZIGZAGS. Count the total number of permutations WITHOUT listing all the possibilities. . l / gigs] 5/ l/A/S » 2 U) laszéZGISi ":(D it) 912‘s] 1a]? ; Cease/'23: 3a (to) gg’y/ og’s/ : 0032).:1" 2 : 3e tv.) (2—, 016’s] 3 z'Céqflj-aze: 36» v.) [allG/ Z)? : C(q/fl-CQI/ou: ‘7; ' ? ‘ 41-3-«2' :4 W) ‘%)°C~,?,./?vCC,) [I «i m.) 0215/ M’s; 2/? : col/.2)- 3- a: 36, ??:CLq/z)- 3-2-1 : «2g / / W44 vat.) og‘s/ (3/ e ...
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This note was uploaded on 11/26/2010 for the course MAT MAT 17C taught by Professor Kouba during the Spring '09 term at UC Davis.

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pracexam2sol 17C - Math 17C (Spring 2007) Kouba Exam 2 Your...

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