6.3 3a.  Find an approximation of the area of theregion R under the graph of the function f on theinterval [−1, 2]. Use n = 6 subintervals. Choose therepresentative points to be the left endpoints of thesubintervals.  f(x) = 6 −x2  Â
_________square units
b. Find an approximation of the area of the region Runder the graph of the function f on the interval [1, 3].Use n = 4 subintervals. Choose the representativepoints to be the right endpoints of thesubintervals.  f(x) =6/x
_________ square units
c. Find an approximation of the area of the region Runder the graph of the function f on the interval [0, 3].Use n = 5 subintervals. Choose the representative pointsto be the midpoints of the subintervals. (Round your answer to onedecimal place.) f(x) =3ex
___________square units
