functions...ATGS

I could not solve this for quite sometime...

lets see who can ...

let f(x)=(2x-Ï€)3 + 2x - cos x

find ddx[f-1(x)] at x=Ï€ [1][1][1]

3 Answers

1
venkateshan ·

hey subho.....
just check out this link 4 da solution......

http://www.targetiit.com/iit-jee-forum/posts/differentiation-2-17388.html

i had also asked the same doubt earlier.....

1
bindaas ·

f(a)=Ï€
x=Ï€2

f'(Ï€2)=3

now use

f^{-1}(f(x))=x \\ \frac{d }{d x}{f^{-1}(f(x))}=1\\ \texttt{apply chain rule} \\ \frac{d }{d x}{f^{-1}(f(a))}=\frac{1}{f'(a)}

\frac{d }{d x}{f^{-1}(\pi)}=\frac{1}{3}

49
Subhomoy Bakshi ·

no i have solved this now...

just gave this as i found the question fascinating!

neways thanks! :)

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