Question
Question: Let f : R ® R be a one onto differentiable function, such that f(2) = 1 and f'(2) = 3, then the valu...
Let f : R ® R be a one onto differentiable function, such that f(2) = 1 and f'(2) = 3, then the value of (dxd(f−1(x)))x=1 is –
A
21
B
31
C
61
D
6
Answer
31
Explanation
Solution
Let f–1(x) = g(x)
So g ¢(x) = f′(g(x))1
g ¢(1) = f′(g(1))1=f′(2)1=31