- #1
vipertongn
- 98
- 0
Homework Statement
find the exact value of cos(arctan(2)+arctan(3))
The Attempt at a Solution
I know that arctan(2) is equivalent to tanx=2 and arctan(3) is equal to tanx=3
I was thinking perhaps sinx/cosx=2 and 3 but I am not sure what numbers to use. I'm kind of weak in my trig rules =( can someone explain to me how I would go about this problem? I know the answer is -sqrt2/2 but I want to know HOW to do it.