Define the function s by
s(t)=⎩⎨⎧t2−4t,sin(2πt),for 0≤t≤4,for t>4.
Let S be an antiderivative of s such that S(2)=3.
(a) For 0≤x≤4, derive an explicit expression for S(x) in terms of x.
(b) Determine the exact value of S(4).
(c) For x≥4, write an expression for S(x) that is valid on the interval 4≤x≤6.
(d) Compute the exact value of S(6). Show all steps leading to your answer.