Sin30=0.5 what is cos150?

1 Answer
Sahar Mulla ❤
Apr 10, 2018

Fact that #sin30°=0.5# isn't required to solve the problem.

#cos150°=cos(180°-30°)=cos(π-30°)=-cos30° = -sqrt3/2# #[ because costheta# is negative in second quadrant. Half a rotation means uptill #π#. But we're #30°# behind yet to hit the line of #180°#. These are the quadrant rules. I hope you've got your concept clear :) #]#

Related questions
Impact of this question
707 views around the world
You can reuse this answer
Creative Commons License