Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

abbie1

Help!! Let f(x)=7x-13. Find f^-1(x). Let f(x)=x^2-16. Find f^-1(x).

  • one year ago
  • one year ago

  • This Question is Closed
  1. saifoo.khan
    Best Response
    You've already chosen the best response.
    Medals 0

    Do you know how to find an inverse?

    • one year ago
  2. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay thanks..

    • one year ago
  3. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    ask if you still need help.

    • one year ago
  4. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    I'm still confused..what am I finding the inverse to in my problem?? @hartnn

    • one year ago
  5. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    ok, let y=7x-13 now to find the inverse, isolate x =... ? then just replace 'x' and 'y' (you can replace before isolating also.)

    • one year ago
  6. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    -7x=-13-y?? why would there be a y in there??

    • one year ago
  7. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    and then divide the whole thing by -7, but they're going to be fractions.

    • one year ago
  8. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    y= 7x-13 add 13 to both sides, then divide by 7 [Let there be fractions, its ok]

    • one year ago
  9. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    So basically you set the problem equal to 7x-13, and either make it equal to y or x?? There is no y in the problem? that's why i am confused

    • one year ago
  10. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    x=-13-y/-7, and then do you want me to solve for x on y=7x-13 or that's what y equals?? So you use x to solve for y and y to solve for x??

    • one year ago
  11. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    y = f(x).. They are the same thing

    • one year ago
  12. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    x and y are the same thing??????

    • one year ago
  13. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    i considered f(x) = y for simplicity. i'll write out steps so that you can understand. y= 7x-13 y+13 = 7x x = (y+13)/7 now to find inverse function just replace x and y y= (x+13)/7 so your inverse function is \[f^{-1}(x)=\dfrac{x+13}{7}\] got this ?

    • one year ago
  14. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    f(x) and y are the same thing, so you re-write it as y = 7x-13

    • one year ago
  15. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    got that part?

    • one year ago
  16. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    Yes THANK YOU!!!!

    • one year ago
  17. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    swop d x for d y.... it becomes x = 7y-13

    • one year ago
  18. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    can you do same thing for f(x)=x^2-16. ?

    • one year ago
  19. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    yep

    • one year ago
  20. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    after swopping, solve for y

    • one year ago
  21. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    7y= x+13 y = (x+13)/7

    • one year ago
  22. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    Yes x=4 + sqrt y

    • one year ago
  23. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    yes, but u have to swop d x and d y back... final answer would be y = 4 + sqrt(x)

    • one year ago
  24. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    did u simplify like this ? \[\sqrt{16+y}=4+\sqrt y \] no, thats incorrect.

    • one year ago
  25. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    by d do you mean the?

    • one year ago
  26. ohimai
    Best Response
    You've already chosen the best response.
    Medals 0

    yep

    • one year ago
  27. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    sqrt. y+16=x^2 (Root over y+16)

    • one year ago
  28. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    yeah, the inverse function will be \[f^{-1}(x)=\sqrt{x+16}\] no further simplification possible.

    • one year ago
  29. hartnn
    Best Response
    You've already chosen the best response.
    Medals 1

    ok ? got it ?

    • one year ago
  30. abbie1
    Best Response
    You've already chosen the best response.
    Medals 0

    Oh got it!!!

    • one year ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.