How do you evaluate $cot 400$ ?

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Answer 1 · 2016-09-29T10:00:09

$cot400^o=1.1918$

Al trigonometric ratios are in a cycle of $2pi$ radians or $360^o$ i.e. their values repeat after $2pi$ radians or $360^o$ ,

Hence, $cotx=cot(360^o+x)=cot(720^o+x)=cot(x-360^o)=cot(x-720^o)$ etc.

Hence $cot400^o=cot(360^o+40^o)=cot40^o$

and from tables $cot40^o=1.1918$

How do you evaluate cot 400cot 400?