Thread: loads of help on functions needed
View Single Post
  #2  
Old November 4th, 2009, 01:31 AM
Grandad's Avatar
Grandad Grandad is offline
MHF Contributor

  
Join Date: Dec 2008
Location: South Coast of England
Posts: 2,282
Country:
Thanks: 154
Thanked 1,276 Times in 1,117 Posts
Grandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud ofGrandad has much to be proud of
Default
Hello pop_91
Quote:
Originally Posted by pop_91 View Post
ok need some help i just cant seem to do these few questions, and i've left it until the last minute as it has to be in tomorrow! aargh! thanks for the help x

1) find the inverse and state the domain f(x) = 1 - 2^x , x E R
Let y = 1 - 2^x

Then:
2^x = 1-y

\Rightarrow x = \log_2(1-y)
So the inverse function is:
f^{-1}(x) = \log_2(1-x)
I presume the question means the domain of the inverse function. The domain of \log(z) is z>0, so here 1-x>0; i.e. the domain is x<1, x \in \mathbb{R}

Grandad
Reply With Quote
The following users thank Grandad for this useful post:
Donate to MHF