Statements (17) Let $a = \frac{1}{\ln 3}$. Then $3^a = e$.\\ (18) $\sin(0.02) < 2\sin(0.01)$.\\ (19) $\arctan(0.01) > 0.01$.\\ (20) $4\int_0^1 \arctan(x)\, dx = \pi - \ln 4$.