Question

Find dy/dx by implicit differentation:
5+3x=sin(xy^7)


I keep getting...
(3-y^7cos(xy^7))/(7xycos(xy^7))
and it's wrong
can someone help me?

Answer 1

differentiate 5+3x giving 3

now sin(xy^7) gives

cos(xy^7) * (y^7 + (dy/dx)x7y^6)

so
3 = cos(xy^7) * (y^7 + (dy/dx)7xy^6)
dy/dx = ([3/ cos(xy^7)] - y^7) / [7xy^6]

Answer 2

Oh okay, thanks for showing the steps so I could see what I got wrong...

Answer 3

5+3x=sin(xy7)
taking derivatives on both sides
3=cos(xy7)(x7y6.dy/dx+y7)
3-y7cos(xy7)=cos(xy7)(7xy6.dy/dx)
dy/dx=3-y7cos(xy7)/cos(xy7)7xy6
that the answer i think so.....the value with y is a power of "y"

Answer 4

Monroe......my answer is more reliable

Answer 5

I got it, thanks for the help.

Answer 6

ok...welcome

Answer 7

lol its the same thing that i did

Answer 8

what makes it more reliable ?!

Answer 9

no...your answer is a bit different.....

Answer 10

no its not ..
you just multiplied numerator and denominator by cos(xy^7)

Answer 11

look at my brackets.

Answer 12

oh yes now i see it.......sorry for that....and welldone