Question

du/dx y-4(x^2)+2=0 I got (8x/y) but that isnt accepted.....

Answer 1

y-4(x^2)+2=0
dy/dx - 8x +0 = 0
dy/dx = 8x
its just 8x

Answer 2

so if y has no coefficient is just turns into 0?

Answer 3

it didn't turn to 0, y turned to dy/dx after differentiating

Answer 4

just to make sure, u want dy/dx in y-4(x^2)+2=0

Answer 5

?

Answer 6

well it turned into yy' right and the dervivative of y is 1 so is that what happened?
and yes, thank you for your help

Answer 7

the derivative of y isn't yy'
its just y'

Answer 8

okay i guess i just understood it wrong..... i have another question if you dont mind sqrt(x)+sqrt(y)=7 and y(9)=16 find y'(9) by implicit differentiation

Answer 9

know implicit diff. ?

Answer 10

yes, find y' as a function of x i came up with (-1/2x^(-1/2))/((1/2)y^(-1/2))

Answer 11

wait, was that y' ?

Answer 12

yes thats what i hope y' is

Answer 13

yes, thats correct, y'=(-x^(-1/2))/(y^(-1/2))
now put ,x=9, y=16

Answer 14

okay thanks i was confused as to what to plug in for y..... thanks again!

Answer 15

welcome :)

Answer 16

if you wouldnt mind i have another question xy^12=1 at (1,-1) find the slope of the tangent line at this point. so i got
x*12y^11 and tried to plug in the points but to no avail..... any suggestions?

Answer 17

\(xy^{12}=1\)
your derivative is incorrect, u need to use product rule.

Answer 18

12xy^11y' + y^12 = 0
now put x=1,y=-1

Answer 19

awesome, thanks!

Answer 20

-12y'+1=0
y'=-1/12
u got this ?

Answer 21

welcome :)

Answer 22

to Find dy/dx in terms of x and y if 7 x y + 4 x + y = 12 would the next step be
7yy'+4+yy' ?

Answer 23

for 7xy, it will be 7yy'+7y
other terms are correct

Answer 24

okay so there will be no x in the answer? and i am confused as to what to do once i have

7yy'+7y+4+yy'

Answer 25

7yy'+7y+4+y' = 0
now isolate y'
Note, last term was also incorrect, its just y'

Answer 26

would it turn into y'=-4/7y or 2y'=-4/7y or neither?