Problem to solve exponential equation

hello. I have a problem when a try solve exp(1/x)=b equation where b is a known number. for example vpasolve(exp(1/x)==3,x) the result is -1.0787658120660760897089735826813e186744862 that's clearly wrong. please help me

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Walter Roberson
Walter Roberson 2018 年 4 月 13 日
編集済み: Walter Roberson 2018 年 4 月 13 日

0 投票

You are right, I am seeing the same thing, but different results.
-2.9994493695148696857379250512264623387666217934763e178433142
I will file a bug report... filed.

その他の回答 (1 件)

James Tursa
James Tursa 2018 年 4 月 13 日
編集済み: James Tursa 2018 年 4 月 13 日

0 投票

Why not solve it directly:
x = 1./log(b)
What's the point of using vpasolve for this?

1 件のコメント

Jose Fernandez
Jose Fernandez 2018 年 4 月 14 日
because the equation that i want solve is exp(-(3.14*ra)/x)+exp(-(3.14*rb)/x)=1 and in this case i cant apply log to solve. but i realize a change of variable x=1/y to solve getting good results. thanks

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