SOLUTION: Use the information given below to find sin(Alpha + Beta). cos alpha = 4/5, with alpha in quadrant I. cos Beta = - 4/5, with Beta in quadrant III. give the exact answe

Algebra ->  Trigonometry-basics -> SOLUTION: Use the information given below to find sin(Alpha + Beta). cos alpha = 4/5, with alpha in quadrant I. cos Beta = - 4/5, with Beta in quadrant III. give the exact answe      Log On


   



Question 1070150: Use the information given below to find sin(Alpha + Beta).
cos alpha = 4/5, with alpha in quadrant I.
cos Beta = - 4/5, with Beta in quadrant III.
give the exact answer not a decimal approximation.
sin (a + B) = __________________
MY NOTES: How is this calculated? I am able to find
sin(B) is -3/5
sin (a) is 3/5
(please verify if I am on the correct track. Is there a calculator for this?) Thank you.
sin (a + B) = __________________

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Use the formula,
sin%28a%2Bb%29=sin%28a%29cos%28b%29%2Bcos%28a%29sin%28b%29
and substitute the values you have and calculated.