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Topic: solve help
Replies: 4   Last Post: Jun 24, 2013 10:59 AM

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Nasser Abbasi

Posts: 6,677
Registered: 2/7/05
Re: solve help
Posted: Jun 22, 2013 8:53 PM
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>> What value of 't' you think will make exp(sin(t)) zero?
>> sin(t) is between -1 and +1. So, just plot exp() between these
>> 2 values and you'll see it is not zero.
>> You have to go to -infinity and beyond to have any luck of
>> making exp() in the limit go to zero.
>> --Nasser

> I am using the solve function to solve the equation ft for t
> clc, clear;
> syms t ft
> ft = exp(sin(t));
> solve(ft,t)
> However, the result of this ^^^ is as follows:
> Warning: Explicit solution could not be found.

>> In solve at 179
> ans =
> [ empty sym ]
> I don't want to solve the equation for a value, but a variable.
>I want the equation t with respect to ft. Is this any clearer now?

Thank you so much, yes, much more clear now.

But the answer is still the same I am afraid. Please re-read what
I wrote earlier.

There is no solution to exp(sin(t))=0, in other words, there is
no 't' which will make exp(sin(t)) zero.

Did you try to plot exp(x) for x=-1..1 ? did you see exp(x)
cross the x-axis anywhere? It does not. So there is no solution,
it is never zero.


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