Solution
= Solution
The <Butcher tableau> has one stage with $a_{11}=1/2$ and $b_1=1$, so it is the <implicit midpoint rule>
$$
y_{n+1}=y_n+h f\left(\frac{y_n+y_{n+1}}2\right).
$$
Again, interchanging the endpoints and changing $h$ to $-h$ leaves the equation invariant. Hence $\boxed{\text{method 3 is time symmetric}}$.