Question

Chain rule of modulus (absolute value) functions.

Answer 1

If I had a function say \[y = |ax^{2}-b| -x \]
how would I take the derivative.

Answer 2

@hartnn Any idea how to approach this?

Answer 3

my first thoughts is to use ,
\(\Large |a|=\sqrt {a^2}\)

Answer 4

alright there we go lets try that

Answer 5

My function was take the derivative of .\[f(x)= |x^{2} -5| -x \]

Answer 6

yup,
go for it,
\(\Large \sqrt{(x^2-5)^2}-x\)

Answer 7

I get\[\frac{ 2(x^{2}-5)(2x) }{ \sqrt{(x^{2}-5)^{2}} } -1\] @hartnn is that what you got?

Answer 8

wait there is no two

Answer 9

yup, except the 2 i got the same thing..

Answer 10

i verified it online too,
http://www.wolframalpha.com/input/?i=derivative+of+%7Cx%5E2-5%7C-x

Answer 11

When I plug in values like say -1. I get \[\frac{ -2 * -4 }{ \pm4 } - 1 \]

Answer 12

why would u plug in -1 ?

Answer 13

because I f(2) = -1

Answer 14

Isn't that right or am I not using the modulus correctly

Answer 15

f(2) is -1 , thats correct.

Answer 16

I GOT IT I GOTI T AHHHH nevermind @hartnn I have another question. new post

Answer 17

ok :)