Final answer:
The function f'(x) = xsin²(x) - 1/x has one critical number on the open interval (0, 2π).
Step-by-step explanation:
The critical numbers of a function are the values of x where the derivative is equal to zero or is undefined. To find the critical numbers of the function f'(x) = xsin²(x) - 1/x, we need to set the derivative equal to zero and solve for x:
xsin²(x) - 1/x = 0
Multiply both sides of the equation by x:
x²sin²(x) - 1 = 0
Then use trigonometric identities to simplify the equation:
(x² - x²cos²(x)) - 1 = 0
x²(1 - cos²(x)) - 1 = 0
x²sin²(x) - 1 = 0
Therefore, there is one critical number on the open interval (0, 2π).