Posted by stacey graham on Saturday, March 27, 2010 at 5:58pm.
find the exact value given that cosA=(1/3) in quad I, sin B=(1/2) in quad 4, and sin C=(1/4) in quad 2
tan(B+C) ?
At the end of my equation I had (sqrt45/15) over (1sqrt15/15) , how do I rationalize or did I make an error in calculation

trig  Reiny, Saturday, March 27, 2010 at 6:25pm
you should have had tanB = 1/√3 and tanC = 1/√45
for tan(B+C) I got (√15  √3)/(√45  1)
(which is the right answer, because I used my calculator to find the actual angles.)
we could change the answer to
(√15  √3)/(3√5  1) and then multiply top and bottom by (3√5 + 1)/(3√5 + 1) if you have to rationalize it.