Inverses - Dr. Fred Kral - Bentley School

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Inverse functions

In general:

f ( f  −1 (x) ) = x

f  −1 ( f (x) ) = x

 

In particular:

ex and ln x

10x and log x

sin x and sin -1 x = arcsin x, etc.

xn and nx = x1/n

x2 and √x = x1/2

x3 and 3x = x1/3

 

Inverses can be verified with the general identities above, or by construction (finding the inverse and comparing with the candidate function for being an inverse).  Constructing an inverse means swapping x and y and solving for the "new" y.

 

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