(adsbygoogle = window.adsbygoogle || []).push({}); Implicit differentiation, whats going wrong!?

Hey people can someone point out to me please where I'm going wrong with part B of this question, can't get it to look the answer in the book, d2y/dx2 = -3(x^6/y^7)- 3(x^2/y^3).

My answer is listed below under part B section, but i can't manipulate it to look like the above answer :S, any help/tips greatly appreaciated cheers,

5. Implicit Differentiation. If x^4 + y^4 = 16, use the following steps to find y''.

(a) Use implicit differentiation to find y',

dy/dx = -x^(3)/y^(3) - too easy

(b) Use the quotient or product rule to differentiate the expression for y' from part (a). Express your answer in terms of x and y only.

d^2/dx^2= ((-x^(3))/(-3y^(4)))*y''-(3x^(2))/(y^(3))

(c) Use the fact that x and y must satisfy x4 +y4 = 16 to simplify your answer to part

(b) to the following expression

d2y/dx2 = -48(x2/y7).

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Implicit differentiation, whats going wrong?

**Physics Forums | Science Articles, Homework Help, Discussion**