Compute T 3 for (x) = x centered at a = 1. Then use a plot of

Compute T₃ for ƒ(x) = √x centered at a = 1. Then use a plot of the error |ƒ(x) − T₃(x)| to find a value c > 1 such that the error on the interval [1, c] is at most 0.25.