Question

Evaluate cos11pi /6
-square root of 3/2
-1/2
1/2
square root of 3/2

Answer 1

`\displaystyle cos (11 \pi)/(6)= cos ((3 \pi)/(2) + ( \pi)/(3))=sin ( \pi)/(3)= sin 60^(\circ)=( \sqrt3)/(2)`

Answer is 4) square root of 3 / 2