Question

if P (2π/3) = ( -1/2 , /3/2) then cos Ø =?

Answer 1

Solution:

$P (2π/3) = ( -1/2 , /3/2) \\\thereforeØ = 2π/3 \\So, \cos Ø = \cos (2π/3) \\= \cos (π-\dfrac π3) \\=-\cos (\dfrac π3) \\=-\dfrac12$