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posted by Elyse on Thursday, July 25, 2013 at 2:32pm.

Find the Laplace transform of: f(t) = cos^(2)(2t)

cos^2(2t) L{cos(t)} = s/(s^2+1) L{f(at)} = 1/a f(s/a), so L{cos(4t)} = 1/4 (s/4)/(s^2/16+1) = s/(s^2+6) L{cos^2(2t)} = L{(1+cos(4t))/2} = 1/2 (L{1} + L{cos(4t)}) = 1/2 (1/s + s/(s^2+16)) = (s^2+8) / (s^3+16s)

Thank you!!

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