What is the limit as ∆t → 0 for ∆y/∆t = (√(t + ∆t) - √t)/(∆t)?​

Tyler enjoys the fish so much that after his birthday his family decides to take him to a famous aquarium a tank at the aquarium is similar to his tank with the scale factor of 8 how many times greater is the volume of the tank at the aquarium than the volume of tyler tank