Question Number 26142 by moxhix last updated on 21/Dec/17
![Prove that If f(x) is Riemann integrable on [a,b] and ∃M>0 s.t. ∀x∈[a,b] (f(x)≠0 and ∣f(x)∣<M and ∣(1/(f(x)))∣<M), then (1/(f(x))) is Riemann integrable on [a,b].](https://www.tinkutara.com/question/Q26142.png)
$$\mathrm{Prove}\:\mathrm{that}\: \\ $$$$\mathrm{If}\:{f}\left({x}\right)\:\mathrm{is}\:\mathrm{Riemann}\:\mathrm{integrable}\:\mathrm{on}\:\left[{a},{b}\right]\:\mathrm{and} \\ $$$$\:\:\:\:\:\exists{M}>\mathrm{0}\:{s}.{t}.\:\forall{x}\in\left[{a},{b}\right]\:\left({f}\left({x}\right)\neq\mathrm{0}\:{and}\:\mid{f}\left({x}\right)\mid<{M}\:{and}\:\mid\frac{\mathrm{1}}{{f}\left({x}\right)}\mid<{M}\right), \\ $$$$\mathrm{then}\:\frac{\mathrm{1}}{{f}\left({x}\right)}\:\mathrm{is}\:\mathrm{Riemann}\:\mathrm{integrable}\:\mathrm{on}\:\left[{a},{b}\right]. \\ $$