Question 65 – A differential equation is given as y” + 5y’ + 6y = 0, y(0) = 2 and y’(0) = 3. By using Laplace transform, an engineer has correctly produced the equation L {y} = (2s + 13) / [(s + 2)(s + 3)] = A / (s + 2) + B (s + 3). (a) Find the values of A and B. (b) The inversed Laplace transform of 1 / (s + a) is given by exp (-at) where a is a constant. If the statement : L {y} = 9 L { exp (-2t) } - 7 L { exp (-3t) } is correct, find the equation of y as a function of t as a solution to the differential equation stated in the beginning of this question. When L {d} = 9 L {b} - 7 L {c}, then d = 9b - 7c with b, c and d are unknowns.
Answer Posted / kang chuen tat (malaysia - pen
Answer 65 – (a) Let (2s + 13) / [(s + 2)(s + 3)] = [A (s + 3) + B (s + 2)] / [(s + 2)(s + 3)]. Then 2s + 13 = As + 3A + Bs + 2B = (A + B)s + (3A + 2B), then A + B = 2 and 3A + 2B = 13. Let 2A + 2B = 4 as first equation by doubling A + B = 2 and 3A + 2B = 13 as second equation, the difference of first and second equations will produce A = 9. When A = 9, B = 2 - A = 2 - 9 = -7. (b) Let d = y, b = exp (-2t) and c = exp (-3t), then y = 9 exp (-2t) - 7 exp (-3t). The answer is given by Kang Chuen Tat; PO Box 6263, Dandenong, Victoria VIC 3175, Australia; SMS +61405421706; chuentat@hotmail.com; http://kangchuentat.wordpress.com.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
Why is post-weld heat treatment sometimes necessary for welded vessels?
How can you determine the proper pipe thickness for a slurry line?
Explain how can viscosity affect the design of a mixer?
Why does catalytic converter used in an automobile?
On what basis are materials to be crushed evaluated apart from size?
hi all i have doe cheical engg, but i have to go for iob po interview so can anybody suggest me abt the kind of qns that can be asked.
Explain what type of pump may be appropriate for a liquid near saturation, a low flow rate, and very limited npsha (net positive suction head available)?
Re: Sugar Cane Bagasse What are the 1. Specific Heat of Bagasse at 50% moisture, 40% moisture and 25% moisture? 2. What is bu;lk density of bagasse at 50% moisture, 40% moisture and 25% moisture? 3. What is specific gravity of bagasse at 50% moisture, 40% moisture and 25% moisture? 4. What is the specific heat of flue gases generated from boiler fuelled by bagasse? 5. What is the specific gravity of flue gases generated from boiler fuelled by bagasse?
what is R1,R2,R3, R4........?
How can you estimate a gas flow based on two pressure measurements?
Are there any methods of preventing cracking of carbon steel welds in refining environments?
Is there any way to repair a valve that is passing leaking internally without taking our process offline?
what is the difference between car seal close/open valves and lock close/open valves?
What are some good estimates for heat transfer coefficients for coils in tanks?
how should i prepare for my placements.i am a student of chemical eng,final year,thapar university