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发表于 2010-6-8 17:53:09
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inv(x)=tan(x)-x
, s) Q4 Y- s" X9 K `7 ~# [) }逆函數可以 用表查 , 或是用牛頓法
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( f1 W' |0 m; O" r[vb6/vba] Office excel also with this moudle # ?# l9 l/ k/ a3 x5 \+ t. z# w
Public Function Inverse_inv(value As Variant)
) i' j& l6 L" `$ q: D( U Dim ape As Double# y6 _& ~- l- L/ d; _ K& w
Dim pe0 As Double
& Y8 ~# g# F7 a. {, I Dim pe1 As Double$ I, p5 s: L8 i) `
ape = (3 * value) ^ (1 / 3)
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If ape >= 1000000000# Then ape = PI / 2: Exit Do$ v: r F: @7 ^$ i* @ r
pe0 = ape
7 s9 x; \ s' c; L$ l b pe1 = ape + (value + ape - Tan(ape)) / (Tan(ape) ^ 2)) g9 c" N; S' I# [$ [9 [
ape = pe1
3 D, Q9 x4 d9 k1 Z; r Loop Until Abs(pe1 - pe0) <= 0.0000001# c2 E7 J$ M7 Q7 \/ p/ a% z: p6 y
Inverse_inv = ape
4 {* u# f' Q, B, |4 j) @# J8 CEnd Function |
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楼主: 冰山
