Question

find the formula for df^-1/dx.

f(x)=(7-x)^3

Answer 1

what's d?

Answer 2

can you find \(f^{-1}(x)\) ?

Answer 3

oh. ok

f(x) = (7-x)^3
y = (7-x)^3
switch y and x
x = (7 - y)^3
third root of x = 7 - y
-y = 3rootx - 7

so
\[f \prime(x) = \sqrt[3]{x} - 7\]

Answer 4

Thanks for the help but that's not an option on the homework for an answer.

Answer 5

The answer should be y = - 3 root x +7

Answer 6

It is the same thing as the above poster's answer except the person forgot to divide by -1

Answer 7

oh yeah, lol sorry about that :P

Answer 8

\[7-x ^{1/3}\]\[-3(7-x)^{2}\]\[x ^{2/3}\]\[-1/3x ^{2/3}\] are the answer options on the homework.

Answer 9

it's 7 - x^1/3