how do i get tan(-1)
$$\underset{\,\,\,\,^{\textcolor[rgb]{0.66,0.66,0.66}{360^\circ}}}{{tan}}{\left(-{\mathtt{1}}^\circ\right)} = -{\mathtt{0.017\: \!455\: \!064\: \!928}}$$
If you mean $$\tan^{-1}$$ then select the 2nd button on the calculator first and use atan (which is the same thing).
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