Question

(cos+ cos y)2 + (sin x + sin y)2 = 4 cos^2x-y/2.​

Answer 1

Answer:

("2cos (" (x + y)/2 ")

Step-by-step explanation:

(2) Using (1) & (2),we obtain, (cosx+cosy) ^2+ (sinx+siny) ... =2+cos(x+y)+cos(x-y)+cos(x-y)-cos(x+y) . (D^2-4) y= e^x + sin2x + cos^2x?