Question

If P = sin(x+y) sin(x-y) and Q = cos(x+y)
cos (x-y), then P+Q = ?
a) Sin 2x
b) Cos 2y
c) Sin 2y
d) Cos 2x

Answer 1

Answer:

(c)

Step-by-step explanation:

i hope it is correct

Answer 2

Answer

P = sin (x + y) sin (x - y) = sin2x - sin2y

Q = cos(x + y) cos (x - y) = sin2x - sin2y

P + Q = sin2x - sin2y + sin2x - sin2y

= Sin 2y