Simplifying the given expression:

Cos²(π/2+a) + cos²(π-a)

Using trigonometric identities:

cos(π/2 + a) = sin(a)
cos(π - a) = -cos(a)

Therefore, the expression becomes:

(sin(a))² + (-cos(a))²
= sin²(a) + cos²(a)
= 1

Therefore, the final simplified form of the given expression is 1.