Hey guys im abit confused with the different quadrants of the trig ratios thing.
I know all trig ratios are positive in 1st quadrant, then sine, tan, cosine only. However, why does:
cos x= -5/11 (solve for x if 0<x<180)
= 117 degrees?
I thought only sine could be positive when greater than 90 degrees and less than 180 (obtuse). Does - sign mean that this negates this rule?
Also, what would happen if sin x= -5/11 (solve for x if 0<x<180)?
I get two answers for x:
x= 153 degrees or 27 degrees. Since sine is positive both in acute and obtuse quadrants, does this mean both answers are valid?
Any help is much appreciated
Thanks in advance!