SOLUTION: Can someone please help me with this question?! Thank you! If cos(alpha)=0.228 and cos(beta)=0.836 with both angles' terminal rays in Quadrant-I, find the values of a) cos(alpha

Algebra ->  Trigonometry-basics -> SOLUTION: Can someone please help me with this question?! Thank you! If cos(alpha)=0.228 and cos(beta)=0.836 with both angles' terminal rays in Quadrant-I, find the values of a) cos(alpha      Log On


   

Question 1169844: Can someone please help me with this question?! Thank you!
If cos(alpha)=0.228 and cos(beta)=0.836 with both angles' terminal rays in Quadrant-I, find the values of
a) cos(alpha + beta)
b) sin(alpha + beta)
Your answers should be accurate to 4 decimal places.
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


(1) Given cos(alpha) and cos(beta) and the fact that both angles are in quadrant I, use sin%28x%29%5E2%2Bcos%28x%29%5E2=1 to find sin(alpha) and sin(beta).

(2) cos%28alpha%2Bbeta%29+=+cos%28alpha%29%2Acos%28beta%29-sin%28alpha%29%2Asin%28beta%29
(3) sin%28alpha%2Bbeta%29+=+sin%28alpha%29%2Acos%28beta%29%2Bcos%28alpha%29%2Asin%28beta%29

You can do the calculations.