How do you evaluate the expression cos(u+v) given cosu=4/7 with 0<u<pi/2 and sinv=-9/10 with pi<v<(3pi)/2?
1 Answer
Jul 31, 2016
Explanation:
Since
let's calculate (1)sin u and (2)cos v:
(1)
in the first quadrant
(2)
in the third quadrant
Then