Answer
Error $(S_2)=0$, so $S_2$ gives the exact value of the integral.
Work Step by Step
Error $(S_N) \leq \dfrac{k_4(b-a)^3}{180N^4} $
For $N=2$, we have:
Error $(S_N) \leq \dfrac{k_4(b-a)^3}{180N^4} \\ \leq \dfrac{(0)(1-0)^3}{180(2)^4} \\ \leq 0$
The actual error is approximately $[121.5000006-121.5 ] \approx 6 \times 10^{-7} $, which is less than $10^{-6}$.
We see that:
Error $(S_2)=0$
So, $S_2$ gives the exact value of the integral.
