4.2) Prove that if f:[a,b]→R is a continuous function, then f∈ R[a,b] [6] 4.3) Let f:[a,b]→R be a Riemann integrable function. Let m,M∈ R be such that m≤f(x)≤M for all x∈[a,b]. Then show that m(b−a)≤∫ a
b
​
f≤M(b−a). [2] 4.4) Give an example of a Riemann integrable function on [a,b] which is not monotonic on [a,b]. [4]