SOLUTION: values of trig functions cot(-120) degrees

Algebra ->  Finance -> SOLUTION: values of trig functions cot(-120) degrees      Log On


   

Question 1165239: values of trig functions
cot(-120) degrees
Answer by Seutip(231) About Me  (Show Source):
You can put this solution on YOUR website!
Values of trig functions
cot%28-120%29+=+1%2Ftan%28-120%29
cot%28-120%29=1%2Ftan%28-120%2B360%29 when you add 360 its ok and will produce same value because it just means one circle, or one revolution
cot%28-120%29=1%2Ftan%28240%29
We all know that
tan 240° = tan (180°+60°)
And tan(180)=0 leaving us with tan(60°)
And we all know that the value for tan(60) is = √3
∴tan 240°=√3
cot%28-120%29=1%2Ftan%28240%29
cot(-120)=(1/√3)
cot(-120)=(1/√3)(√3/√3) we multiply √3/√3 to rationalize
Therefore:
cot(-120)=(√3/3)
Hope that helps.