If cos theta =-2/3, which of the following are possible?

Question

anonymous · Answer

attachment

***[isuru]*** · Answer

do u know about the quadrants ... i mean the first quadrant second quadrant... up to forth quadrant ?

anonymous · Answer

yes. i don't know the specific rules for each quadrant though. im having a rough time with this.

***[isuru]*** · Answer

so... to solve this...
 first do this simple thing...|dw:1392142813245:dw|

***[isuru]*** · Answer

if  u understand wt i did... 
       we can write...
                  tan theta = sqrt(5) / 2
                  sin theta = sqrt(5) /2

***[isuru]*** · Answer

now the problem is to find  whether the sin and tan values r positive and negative

anonymous · Answer

so to find that we need to know which quadrant its in right?

***[isuru]*** · Answer

|dw:1392142949633:dw|