In Exercises 13–24, find the derivative of y with respect to the appropriate variable.
21. y = ln(cosh v) - 1/2 tanh²v

In Exercises 59–86, find the derivative of y with respect to the given independent variable.

61. y = 5√s

Use l’Hôpital’s rule to find the limits in Exercises 7–52.

39. lim (x → ∞) (ln 2x - ln(x + 1))

Evaluate the integrals in Exercises 39–56.

41. ∫2y dy/(y²-25)

In Exercises 7–26, find the derivative of y with respect to x, t, or θ, as appropriate.

y = ln(e^(θ)/(1+e^θ))

Verify the integration formulas in Exercises 37–40.

39. ∫x coth⁻¹(x)dx = ((x²-1)/2)coth⁻¹(x) + x/2 + C

Evaluate the integrals in Exercises 53–76.

57. ∫dx/(x√(25x²-2))