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Topic: How to approximate tangent function in interval [-Pi/4,Pi/4]
using polynomial

Replies: 5   Last Post: Sep 2, 2012 4:57 PM

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Axel Vogt

Posts: 1,039
Registered: 5/5/07
Re: How to approximate tangent function in interval [-Pi/4,Pi/4]
using polynomial

Posted: Sep 1, 2012 3:26 PM
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On 31.08.2012 13:51, giridhar.t@gmail.com wrote:
> Hi,
>
> I'm trying to approximate tan(x) using polynomial in the interval [-Pi/4, Pi/4].
> What is the best method to do this?
> I searching I found Chebyshev, Talyor or any other method.
> Thank you


Not sure what you mean by 'best' and why it should be polynomial.
In that case try 'chebpade' or 'minmax' for [0 .. Pi/4] and do
some corrections in the endpoints (use correct Digits:= ... ).

One classical is tan(x) ~ x + x^3 P(x^2)/Q(x^2) for that range,
which is a rational function.







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