Question

verify that this is an identity.
sin(x+y)+sin(x-y)=2sinxcosy

Answer 1

use the addition and subtraction angle formulas for sine on the left hand side, then "simplify"

Answer 2

sinAcosB+cosAcosB??

Answer 3

for the first part \(\sin(x+y)\) yes

Answer 4

for the second part it would be \[\sin(x)\cos(y)-\sin(y)\cos(x)\]

Answer 5

add them and you get your answer