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发表于 2010-6-8 17:53:09
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inv(x)=tan(x)-x5 R3 @) v2 [" r5 q4 d/ @3 K
逆函數可以 用表查 , 或是用牛頓法
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) k F' @3 }" u) P; M, ]$ U[vb6/vba] Office excel also with this moudle 0 s+ t/ W- m. t9 D; O. O" L
Public Function Inverse_inv(value As Variant)
* V N0 n- n) j, q: ?# M5 C! V. x Dim ape As Double% i0 w( I) h8 M' E
Dim pe0 As Double( `' I/ Z' M) P* r
Dim pe1 As Double
1 c& D. h4 S( S ape = (3 * value) ^ (1 / 3)
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If ape >= 1000000000# Then ape = PI / 2: Exit Do E+ d' e' |/ N
pe0 = ape5 ~0 F+ U& H" r
pe1 = ape + (value + ape - Tan(ape)) / (Tan(ape) ^ 2)& c( ]2 h, _. ^3 k
ape = pe10 h4 o' w0 c& d6 c y# S( M
Loop Until Abs(pe1 - pe0) <= 0.0000001
K1 b: h2 Y" n Inverse_inv = ape. f/ L% B* F2 S8 t( s9 B: k8 P B
End Function |
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楼主: 冰山
