dear cma,81is not good.

來源: 於 2012-01-02 16:54:15 [舊帖] [給我悄悄話] 本文已被閱讀：次

If b=2d,a=20.we get anwser no err.It is 72,71 or 70. If using your formula we get

81.It is not right.A formula should be right in their domain.the  (90-a)/b is getting in

times,out is almost the same, so we have 2(90-a)/b times as the ...