Quantcast

A community for students. Sign up today!

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

abannavong

  • 2 years ago

calc help!!!! how do you differentiate absolute values?!?!??!?!

  • This Question is Closed
  1. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    y= abs(3x-1)

  2. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    when x > 1/3 this is the same as y= 3x-1 when x< 1/3 it is y= -3x+1

  3. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so what rule can u use for the absolute value problems or can u do it on ur calculator

  4. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    bc i know you cant use the product rule or the quotient rule or the power rule it seems like or the chain rule

  5. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    one other thing, dy/dx is undefined at x= 1/3 use the power rule d/dx a x^n = a n x^(n-1)

  6. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    how would u use the power rule for the abs(3x-1)

  7. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    would u set (3x-1)^1 ?

  8. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    you get 3 different answers, depending on x x> 1/3 d/dx (y= 3x-1) x= 1/3 undefined x<1/3 d/dx (y= -3x+1) d/dx y = dy/dx d/dx (3x^1 - 1) = d/dx 3x^1 + d/dx (-1) can you finish?

  9. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    yeah now i can oh ok and also i have another question for absolute values differentiate y= abs(x^2-5x+4) would u jst factor it out first?

  10. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    and use the product rule?

  11. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    for abs(x^2-5x+4) you have to find the values of x where this stays positive and the regions where it is negative (then replace abs with - )

  12. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    First finish the first problem, then repost this quadratic, because it is more complicated, and might take time to explain

  13. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    kk

  14. TuringTest
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    if I may add, one trick to differentiating absolute value can be to use the definition\[|x|=\sqrt{x^2}\]let\[u=x^2\]then\[\frac d{dx}\sqrt u=\frac{u'}{2\sqrt u}=\frac{2x}{2|x|}=\frac x{|x|}\]

  15. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    can u differentiate it on your calculator?

  16. TuringTest
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    I rely on my brain for differentiation usually, I've lost track of what handheld calculators are good for besides graphing and handling ugly nmbers

  17. TuringTest
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    numbers*

  18. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i dont think my teacher has taught us how to differentiate absolute values yet but she assigned us an assignment with like 2 absolute value problems im still a bit confused on how to differentiate it

  19. TuringTest
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    I just showed you one way

  20. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    what r the other ways

  21. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    #stillconfused

  22. phi
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    btw, turing I think you should tweak your rule to x dx/|x|

  23. L.T.
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    @abannavong, another way to find the derivative is to set up the difference quotient and multiply by the conjugate of the numerator (|x+h|-|x|)/h-->((|x+h|-|x|)(|x+h|+|x|))/(h*(|x+h|+|x|)) Hint: When you square an absolute value, you can drop the absolute value signs

  24. abannavong
    • 2 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    oh ok thanks @L.T.

  25. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Ask a Question
Find more explanations on OpenStudy

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.