4sin(a-2π) + 11cos(π/2 + a)

Using trigonometric identities:

4sin(a-2π) = 4sin(a)cos(2π) - 4cos(a)sin(2π) = 4sin(a)

11cos(π/2 + a) = 11sin(a)

Therefore, the expression simplifies to:

4sin(a) + 11sin(a) = 15sin(a)

So, the final simplified expression is 15sin(a)