What is the derivative of an inverse function?
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science
space and astronomy
The Derivative of an Inverse Function. (f−1)′(a)=pq. f′(f−1(a))=qp. (f−1)′(a)=1f′(f−1(a)).
Hereof, how do you find the derivative of an inverse function?
Finding the Inverse of a Function
- First, replace f(x) with y .
- Replace every x with a y and replace every y with an x .
- Solve the equation from Step 2 for y .
- Replace y with f−1(x) f − 1 ( x ) .
- Verify your work by checking that (f∘f−1)(x)=x ( f ∘ f − 1 ) ( x ) = x and (f−1∘f)(x)=x ( f − 1 ∘ f ) ( x ) = x are both true.
Similarly, you may ask, how are the derivatives of inverse functions related?
Derivatives of inverse functions. Functions f and g are inverses if f(g(x))=x=g(f(x)). For every pair of such functions, the derivatives f' and g' have a special relationship. Learn about this relationship and see how it applies to ??ˣ and ln(x) (which are inverse functions!).
Expression | Derivatives |
---|---|
y = cos-1(x / a) | dy/dx = - 1 / (a2 - x2)1/2 |
y = tan-1(x / a) | dy/dx = a / (a2 + x2) |
y = cot-1(x / a) | dy/dx = - a / (a2 + x2) |
y = sec-1(x / a) | dy/dx = a / (x (x2 - a2)1/2) |