The ` in Solve results

Asked May 21 '16 at 14:44

Active May 24 '16 at 14:39

Viewed 57 times

I assign the result of a Solve to the variable eq8. Then I attempt to use this result in the definition of a function as follows:

In[166]:= eq8 = Solve[eq7, {V1}]
Out[166]= {{V1 -> -1.02 (461.185 - 1. im)}}
In[177]:= Vstrom = eq8[[1, 1, 2]]
Out[177]= -1.02 (461.185 - 1. im)
current[im_] := N[Vstrom]

This does not work. With copy of Out[177] and paste it - instead of Vstrom - into N[] I find

current[im_] := N[-1.0200000000000002` (461.184642121376` - 1.` im)]

When eliminating these characters, my function works. Why can't I use the notation N[Vstrom]? After all, these-characters in the above number are just the spec. that the number shall have maschine accuracy. So why does the funktion not work with these characters present?

edited May 24 '16 at 14:39

asked May 21 '16 at 14:44

Robert Brusa

2

This is related Meaning of backtick in floating-point literal. – Artes May 21 '16 at 14:52
I have joined another user in voting to close this as a duplicate. Please read the Q&A linked in the banner at the top of your post. If this does not solve your problem please edit your question to describe exactly how your situation is different. – Mr.Wizard May 21 '16 at 16:16
1

Set $NumberMarks = False if the backticks annoy you. – J. M.'s missing motivation May 24 '16 at 14:55
I think the question here is "Why can't I use the notation N[Vstrom]", not about tick notation. The problem here is current[im_] := N[Vstrom], where the expectation was that im would get replaced. But with :=, the RHS isn't evaluated, so im doesn't appear. Use current[im_] = N[Vstrom] instead. – John Doty May 24 '16 at 18:08

The ` in Solve results

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