To find the derivative of the inverse of a function, we can use the formula:
(f-1)'(y) = 1 / f'(x)
where y = f(x). From the question, we have:
f(x) = 1 / x3.
First, we need to find the derivative of f(x):
f'(x) = -3 / x4.
Next, we need to express x in terms of y. Since y = f(x), we can write:
y = 1 / x3 => x3 = 1 / y => x = (1 / y)1/3.
Now, we substitute x back into the derivative:
(f-1)'(y) = 1 / f'(x)
(f-1)'(y) = 1 / (-3 / x4) = -x4 / 3.
Finally, we substitute x = (1 / y)1/3:
(f-1)'(y) = -((1 / y)1/3)4 / 3 = -1 / (3 * y4/3).
So the derivative of the inverse function is:
(f-1)'(y) = -1 / (3 * y4/3).