In many cases, the round-offerror can be managed, even over really complex computations, such that the top 6-8 decimal places are correct.
在许多情况下，舍入误差是可以控制的，即使在很复杂的计算，使得上部6 - 8位小数是正确的。
2
However, for negative values of x, roughly -4 and lower, the algorithm used to calculate Math.exp is relatively ill-behaved and subject to round-offerror.