Prove sin(n+1)sin(n+2)x+cos(n+1)x cos(n+2)x = sin(x+y).

Following are the prove of given question is given below

Step-by-step explanation:

In the given question RHS side is incorrect .The correct question is

sin(n+1)x sin(n+2)x + cos(n+1)x cos(n+2)x = cosx

LHS

Here

x =(n+1)x

y=(n+2)x

So

cos(-x)

cos(x) =RHS

2x3 – 6x2 – 14x + 24 square centimeters

if i'm wrong i'm sorry : )

yes because there is exactly one y value for every x value

for function there can't be more than one value for every x value