Question 151205: sin(x+y)-2sinx+sin(x-y)/cos(x+y)-2cosx+cos(x-y)= tan x: sin(x+y)-2sinx+sin(x-y)/cos(x+y)-2cosx+cos(x-y)= tan x Answer by Edwin McCravy(2087) (Show Source):
We need these four identities to use on the left side:
Cancel positive and negative like terms
in numerator and in denominator:
Combine like terms:
Factor out in the top and in the
bottom:
Cancel the 's and the 's.
Then use identity
Edwin
