Question

Pls help with the 3rd one

Answer 1

Answer:

Step-by-step explanation:

Cos(π/4 - x)Cos(π/4 - y) - Sin(π/4 - x)Sin(π/4 - y)

//We know that CosACosB - SinASinB = Cos(A+B)

=> Cos(π/4 - x + π/4 - y)

=> Cos(2π/4 - (x+y))

=> Cos(π/2 - (x+y))

=> Sin(x+y)           (∵ Cos(90-θ) = Sinθ)

Answer 2

$\large { \fcolorbox{gray}{black}{ ✔\: \textbf{Verified \: answer}}}$

The value is Sin(x + y)