SOLUTION: Find sin B and cot B if cosB=-1/4 and tan B>0.

Algebra ->  Trigonometry-basics -> SOLUTION: Find sin B and cot B if cosB=-1/4 and tan B>0.      Log On


   

Question 180062: Find sin B and cot B if cosB=-1/4 and tan B>0.
Found 2 solutions by stanbon, HyperBrain:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find sin B and cot B if cosB=-1/4 and tan B>0.
------------
If cos(B) = -1/4, x=-1 and r = 4
Then y = sqrt(r^2 - x^2) = sqrt(16-1) = sqrt(15)
---------------------
So sin(B) = y/r = sqrt(15)/4
and cot(B) = x/y = -1/sqrt(15)
=====================================
Cheers,
Stan H.

Answer by HyperBrain(694) About Me  (Show Source):
You can put this solution on YOUR website!
IF sin B=a/c, cos B=b/c, and tan B=a/b, then
a%5E2%2Bb%5E2=c%5E2
cosB=-1/4 so b=-1 c=4
a=sqrt%28%28-1%29%5E2%2B4%5E2%29=sqrt%281%2B16%29=-sqrt%2817%29
tan B=a/b... for tan B>0, a<0 since b<0.
sin B=-sqrt%2817%29%2F4
cot B=1%2F%28-sqrt%2817%29%2F-1%29=1%2Fsqrt%2817%29=sqrt%2817%29%2F17
Power up,
HyperBrain!
Stop this mess! Click here