SOLUTION: if cos(x+y)=0.7547 and cos(x-y)=0.9703, then find the value of cos(x)cos(y).

Algebra ->  Trigonometry-basics -> SOLUTION: if cos(x+y)=0.7547 and cos(x-y)=0.9703, then find the value of cos(x)cos(y).      Log On


   

Question 445211: if cos(x+y)=0.7547 and cos(x-y)=0.9703, then find the value of cos(x)cos(y).
Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!

 cos(x+y)=0.7547 and cos(x-y)=0.9703

find the value of cos(x)cos(y)

cos(x+y) = cos(x)cos(y) - sin(x)sin(y) = 0.7547
cos(x-y) = cos(x)cos(y) + sin(x)sin(y) = 0.9703  Now add these eqs.:
-----------------------------------------------
          2cos(x)cos(y)                = 1.7250 

           
          2cos(x)cos(y) = 1.7250

Divide both sides by 2:

           cos(x)cos(y) =  .8625
          
Edwin