Why is Fma not entirely correct?

Fma, or the First Midpoint Approximation, is not entirely correct because it relies on simplifying assumptions that may not hold true in all scenariOS. It assumes linear behavior over the interval, which can lead to inaccuracies when dealing with nonlinear functions. Additionally, the approximation may not account for variations in curvature, resulting in errors in estimating areas or values. Thus, while Fma can be useful for quick estimates, it may not provide precise results for complex functions.