The range of surface integral ∫ (a ^ 2 + x ^ 2 + y ^ 2) ^ 0.5 DS is the upper part of sphere x ^ 2 + y ^ 2 + Z ^ 2 = a ^ 2

The range of surface integral ∫ (a ^ 2 + x ^ 2 + y ^ 2) ^ 0.5 DS is the upper part of sphere x ^ 2 + y ^ 2 + Z ^ 2 = a ^ 2

Is it wrong? Should it be ∫ (a ^ 2-x ^ 2-y ^ 2) ^ 0.5 DS