Use the definition of the laplace transform for cos(2t) => where a is ∞ and b is 0

Can someone, me with this. i really need with this

Need solving this 2nd limit problem.

Kilgore trout creates a new scale to diagnose depression. however, his scale only assesses one symptom of depression while ignoring others. which of the following is his new scale most likely lacking? a) test-retest reliability b) discriminant validity c) criterion validity d) alternate-forms reliability e) content validity f) none of the above