Partial differentiation

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Iv forgotten the basics of this. How do we go about differentiating 3x^2 y^2 w.r.t y? I know the answer is 3x^2 y^2 but could someone explain this for me please?
 

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  • #2
cristo
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Iv forgotten the basics of this. How do we go about differentiating 3x^2 y^2 w.r.t y? I know the answer is 3x^2 y^2 but could someone explain this for me please?
You want to perform [tex]\frac{\partial}{\partial y}(3x^2y^2)[/tex].

You would simply treat the function of x as a constant and differentiate y normally, thus yielding [itex]6x^2y[/itex].

However, this is not what your answer is, so I wonder whether it is the correct question?
 
  • #3
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ooops im getting myself all confused now. I know how to do partial differentiation after all. I was reading the wrong solution as the question was z = x^2 y^2 and ofcourse dz/dy would = 3x^2 y^2 !!
 
  • #4
cristo
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ooops im getting myself all confused now. I know how to do partial differentiation after all. I was reading the wrong solution as the question was z = x^2 y^2 and ofcourse dz/dy would = 3x^2 y^2 !!
Erm.. no it wouldn't.

Unless you mean z=x2y3, in which case, dz/dy would be the answer you quoted.
 
  • #5
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i need some sleep!! Yeah i meant y^3 lol !
 
  • #6
Gib Z
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Its a big warning flag when the derivative is equal to the original function and doesn't involve e in it....
 

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