$0=1$ through integrals?
137648
What is the mistake in doing integration by this method?
91775
Show that $\int_0^1 f^2(x)dx\geq 3$, if $f:[0,1]\to \mathbb{R}$ is an integrable function s.t. $\int_0^1 f(x)dx=\int_0^1 xf(x)dx=1$
94869
Show that $ \int_{k}^{2} \frac{1}{f(y)} =1$
30860
Prove that $f(x)=0$ in $[-1,1]$.
138054
Proving that $\int_0^1 f(x)e^{nx}\,{\rm d}x = 0$ for all $n\in\mathbb{N}_0$ implies $f(x) = 0$
6892
Why is it not true that $\int_0^{\pi} \sin(x)\; dx = 0$?
53830
Evaluate $ \int_{0}^{1} \ln(x)\ln(1-x)\,dx $
58647
Show that $f$ is integrable and $\int_{I} f=0$
24589
Integral of $1/(x^2-1)^2$
148826
Integral of $ 1 \, / \, (1 + a \, \cos(x) )$
47206
$-1 = 0$ by integration by parts of $\tan(x)$
131876
Show that $\int_{a}^{b}{x^{n}f(x)dx}=0$, then $f=0$
80060
Is $\frac{1}{\infty}$  equal zero?
41779
Is $x/x$ equal to $1$
30694
Show that there exist $[a,b]\subset [0,1]$, such that $\int_{a}^{b}f(x)dx$ = $\int_{a}^{b}g(x)dx$ = $\frac{1}{2}$
122076
A one line proof that one is zero using Mathematica 10
80733
integration of function equals zero