Differentials Question Invovling Square Root

Question

I don't really understand this one, been trying for this game but cannot understand it that well.

Let y = 4√x.

Find the change in y, yΔ when x = 2 and Δx = 0.1

Find the differential dy when x = 2 and dx = 0.1

Answer 1

^{Δy = 4√(2.1) - 4√(2) = 0.1397;}

^{dy = y'dx = 2/√xdx = 2/√2·0.1 = 0.1414}