If x and y are acute angles such that 
, prove that 
.
Now we will calculate value of sinx and siny
Hence,
Cos(x - y) = cosx.cosy + sinx.siny
1
If x and y are acute angles such that , prove that .
Now we will calculate value of sinx and siny
Hence,
Cos(x - y) = cosx.cosy + sinx.siny