# Thread: Funtion bessel

1. ## Funtion bessel

Hello to everybody!
I have a problem with Bessel funtion.
Can I say that Jo^2(x)=Jo(x)*Jo(x)

2. If you asking that $\displaystyle J_{\mu} ^2 (x) = J_{\mu} (x) J_{\mu}(x)$ the answer is yes. The same thing with other functions too. For example, $\displaystyle \sin^2 x = \sin x \cdot \sin x$.

3. Originally Posted by ThePerfectHacker If you asking that $\displaystyle J_{\mu} ^2 (x) = J_{\mu} (x) J_{\mu}(x)$ the answer is yes. The same thing with other functions too. For example, $\displaystyle \sin^2 x = \sin x \cdot \sin x$.
However it's a notation to be deprecated as it allows ambiguous notation since we also have:

$\displaystyle J_{\mu} ^2 (x) = J_{\mu} (J_{\mu} (x))$

to be encouraged is:

$\displaystyle (J_{\mu} (x))^2 = J_{\mu} (x) J_{\mu}(x)$

The same goes for sin, also I don't like the usage $\displaystyle \sin x$ rather than $\displaystyle \sin (x)$

RonL

4. Originally Posted by CaptainBlank $\displaystyle J_{\mu} ^2 (x) = J_{\mu} (J_{\mu} (x))$
But this does not make sense. Bessel function's domain is usually positive. While the range is both positive and negative. So when you compose them you get a problem.

5. Originally Posted by ThePerfectHacker But this does not make sense. Bessel function's domain is usually positive.
Why don't you check that, what is usual for one person is not neccessarily so for another.

RonL

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