sin-1(11sin(13)/6.8)

It's sin^-1 Melody:

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\frac{{\mathtt{11}}{\mathtt{\,\times\,}}\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}{\left({\mathtt{13}}^\circ\right)}}{{\mathtt{6.8}}}}\right)} = {\mathtt{21.339\: \!374\: \!187\: \!23^{\circ}}}$$

I will assume that it is 13 degrees and that you only want a first quadrant solution

$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}^{\!\!\mathtt{-1}}{\left({\mathtt{11}}{\mathtt{\,\times\,}}\left({\frac{\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{sin}}{\left({\mathtt{13}}^\circ\right)}}{{\mathtt{6.8}}}}\right)\right)} = {\mathtt{21.339\: \!374\: \!187\: \!23^{\circ}}}$$

And that is the only solution.

I think that is right  

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**I had made 2 mistakes here (I think I have fixed both)

First, as Alan pointed out, I used cos-1 instead of sin-1.  

The second mistake I made was 'forgetting' that sin-1 is only defined for $$-90^0\le x \le 90^0$$

So I am going to fix both these problems and leave the answer correct. (That is the plan)

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**What is the symbol for integers in LaTex?

Thanks Alan