What is $(11pi)/6$ in degrees and hence find $cos((11pi)/6)$ ?

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Answer 1 · 2017-03-28T14:40:32

$cos((11pi)/6)=sqrt3/2$

As $pi$ radians are equal to $180^@$

$1$ radians are equal to $180^@/pi$

$(11pi)/6$ radians are $(cancel(180)30^@)/cancelpixx(11cancelpi)/(cancel6^1)$

= $30^@xx11=330^@$

and $cos((11pi)/6)=cos330^@$

= $cos(360^@-30^@)$

= $cos(-30^@)$

= $cos30^@$

= $sqrt3/2$

What is (11pi)/6(11pi)/6 in degrees and hence find cos((11pi)/6)cos((11pi)/6)?