Let y=y(x) satisfy dxdy=y−2x with y(0)=1. A tangent-line approximation is used with step size h=0.5. The first estimate y^1 approximates y(0.5), and the second estimate y^2 approximates y(1.0) by repeating the procedure starting from (0.5,y^1). Because y′′(x)=y′−2, which description of the two estimates is correct?
a) Both y^1 and y^2 are underestimates of the actual solution values.
b) Both y^1 and y^2 are overestimates of the actual solution values.
c) y^1 is an overestimate and y^2 is an underestimate of the actual solution values.
d) y^1 is an underestimate and y^2 is an overestimate of the actual solution values.