Step-by-step explanation:
Use the Second Fundamental Theorem of Calculus.
If g(x) = ∫ₐᵇ f(t) dt, then g'(x) = f(b) db/dx.
In this case, g(x) = ∫₁ˣ 1/t dt. Therefore:
g'(x) = 1/x d(x)/dx
g'(x) = 1/x
