Question

Where does the X come from?

Answer 1

http://www.math.rutgers.edu/~sferry/MA135F14/135-f14/Fall2009ANS.pdf
Number 9. Where does the X^8X come from

Answer 2

in the answer

Answer 3

y =x^(8x)

Answer 4

I see that

Answer 5

remember the power expansion log rule?

Answer 6

in the first step he uses that to bring the 8x down in front on the left side

Answer 7

yes i understand that

Answer 8

dy/dx= x^n
nx^(n-1)

Answer 9

I just dont understand the second part

Answer 10

I know derivative of y is 1/y dy/dx

Answer 11

but how is the derivative of 8xlnx= 8lnx+8x*1/x

Answer 12

ln y =ln (x^(8x))

Answer 13

ah its the chain rule!

Answer 14

then
ln y =x8 ln (x)

Answer 15

log rule

Answer 16

oh the product rule what a fluttering idiot

Answer 17

product rule yea not chaing rule lol

Answer 18

i am talking about how stupid i am

Answer 19

so how does x^8x come back in the end

Answer 20

he/she use the log role to solve the problem...
1- take the ln for both side... ln y =ln (x^(8x))
2-

Answer 21

wait

Answer 22

I understand all the steps except the end

Answer 23

I just dont understand the last step

Answer 24

2- rewrite the eq. using log rule
ln y= 8x ln x

Answer 25

last step puting y value

Answer 26

you're really not answering my question

Answer 27

I am asking how did the x^8x appear at the end

Answer 28

dy/dx (y)= 1/y y' .....

Answer 29

yes i understand that step

Answer 30

the y value...

Answer 31

goes to the right side i understand but in the last step it disappeared

Answer 32

the Y disappeared at the end

Answer 33

it goes y'=x^8x(8lnx+8)

Answer 34

yes putting the value of it which is x^8x

Answer 35

I finally understand

Answer 36

Thank you

Answer 37

YW

Answer 38

OH DUUDE, because its earlier defined as y literally equalling x^8x, you can substitute it when you move the 1/y over

Answer 39

I was trying to understand that since the beginning

Answer 40

i always thought of that as the last thing in my classes lol

Answer 41

lol

Answer 42

i thought its history of math question -.-