Question

Find the Laplace transform of the function f(t) = cos2t. (a) (2s^2+4)/2s(s^2-4) (b) (2s^2-4)/2s(s^2-4) (c) (2s^2-4)/2s(s^2+4) (d) (2s^2+4)/2s(s^2+4) This question was posed to me in an international level competition. This intriguing question originated from Operational Transforms topic in chapter Intoduction to the Laplace Transform of Network Theory Select the correct answer from above options network theory questions and answers, network theory questions pdf, network theory question bank, network theory gate questions and answers pdf, mcq on network theory pdf, gate network theory questions and solutions, network theory mcq Test , ies network theory questions, Network theory Questions for GATE EC Exam, Network Theory MCQ (Multiple Choice Questions)

Answer 1

Right choice is (d) (2s^2+4)/2s(s^2+4) The explanation: The Laplace transform of the function f(t) = cos2t is L (cos2t) = L((1+cos2t)/2) = L(1/2)+L(cos2t/2) = 1/2[L(1)+L(cos2t)] = (2s^2+4)/2s(s^2+4).