Question Number 48769 by somil last updated on 28/Nov/18
Answered by Abdulhafeez Abu qatada last updated on 28/Nov/18
$${cosx}\:=\:{cos}\left(\mathrm{60}°\:−\:\mathrm{30}°\right) \\ $$$${cosx}\:=\:{cos}\left(\mathrm{30}°\right) \\ $$$${x}\:=\:\mathrm{30}° \\ $$