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发表于 2010-6-8 17:53:09
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inv(x)=tan(x)-x
! x, g! a2 g+ k8 C6 v逆函數可以 用表查 , 或是用牛頓法
S- s& P/ K8 H+ d: L
- ^) E# M* f2 C; a t# ]7 [[vb6/vba] Office excel also with this moudle 5 }4 J. B/ h7 c2 R V5 T7 J* R3 T' O
Public Function Inverse_inv(value As Variant)
% W3 t/ b* a, K1 C Dim ape As Double
) }2 ]% N" C/ h3 a+ L" _9 o Dim pe0 As Double4 u# n( D$ k: K* e
Dim pe1 As Double
3 x; d; v( U9 `! J# ^ ape = (3 * value) ^ (1 / 3)/ }! f7 ^, [; D9 q
Do% ]. L' L. u- s' w3 W% j
If ape >= 1000000000# Then ape = PI / 2: Exit Do0 x |/ i5 U. W4 d( @$ J4 w
pe0 = ape
3 c% i" I! K Q$ t! K: u0 K0 u4 Y pe1 = ape + (value + ape - Tan(ape)) / (Tan(ape) ^ 2)7 e' Q8 l4 h, R+ N+ ~
ape = pe11 k. T% d2 G9 ?# F, ] e" y
Loop Until Abs(pe1 - pe0) <= 0.00000010 a) T3 T* O3 V6 k. ?$ U
Inverse_inv = ape
& f( S: k4 d( b3 ^ ^- EEnd Function |
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