/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q 107E Question 107: Let â„• be the set... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Question 107: Let ℕ be the set of all positive integers, 1, 2, 3,…. We define two functions f and g fromℕ to ℕ:

f(x)=2x, for all x in â„•

g(x)={x2 â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰i´Ú xisevenx+12 â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰i´Úxisodd

Find formulas for the composite functionsg(fx) and f(gx). Is one of them the identity transformation fromâ„• to â„•? Are the functions fand g invertible?

Short Answer

Expert verified

The formulas aregfx=x , fgx=x â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰,xisevenx+1 ,xisodd,gfx is an identity transformation. The functions fand g are invertible.

Step by step solution

01

Write the given data:

Given two functions f and g fromâ„• to â„•:

fx=2x,for all x inâ„•

gx=x2 â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰i´Ú xisevenx+12 â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰i´Úxisodd

02

Find  g ( f ( x ) )

The functionfx=2xis even, solve for the function as:

gfx=g2x=2x2=x

Hence,g ( f ( x ) ) = x for all x.

03

Find  f ( g ( x ) ) 

Let xis even, then

fgx=fx2=2x2=x

If x is odd, then

fgx=fx+12=2x+12=x+1

Thus, fgx=x â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰,xisevenx+1 ,xisodd

04

Check identity transformation

Since,g ( f ( x ) ) = x for all x, sog ( f ( x ) ) is an identity transformation.

05

Check whether f and g are invertible

Now, since f−1x=x2

And g−1x=2x â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â¶Ä‰â€‰â¶Ä‰â¶Ä‰,xiseven2x+1 â¶Ä‰â¶Ä‰, xisodd

Therefore, f and g are invertible.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Study anywhere. Anytime. Across all devices.