Let F [A B] R F(X) = 1 IfcLt;XLt;D

0 if a lt;gt;lt;c
Let a, b, c, d E R such that a lt; c lt; d lt; b. Let f : [a, b] – R, f(x) :=
1 ifclt;xlt;d.
0 ifd lt;xlt;b
Prove that f is Riemann integrable on [a, b] and that
f =d-c.
Remark: The function f defined above is called an elementary step function.
Hint: Do not solve this question by directly applying the definition of Riemann integrability.
Instead, combine already known results on Riemann integrability.Math