(a) Show that all the solutions of the linear equation u′+a(t)u=0, t∈[0,∞), where a:[0,∞)→[0,∞) is a continuous function, are always bounded if ∫∞0a(s)ds<∞ .
(b) Consider the equation (1+t)2u′−u=0, t∈[0,∞) .
(i) Find the unique solution.
(ii) Show that ∣u(0)∣≤∣u(t)∣<∣u(0)∣e, for all t∈[0,∞) . How you are connecting this result with the problem (2)(a) ?
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