## shamil98 one year ago $\text{Find}~ f_{xxyzz}~ \text{for} f(x,y,z) = z^4y^3 \ln x$ is this right : $f_x = \frac{ z^4y^3 }{ x }$ $f_{xx} = -\frac{ z^4y^3 }{ x^2 }$ $f_{xxy} = -\frac{ 3z^4y^2 }{ x^2 }$ $f_{xxyz} = -\frac{ 12z^3y^2 }{ x^2 }$ $f_{xxyzz} = -\frac{ 36z^2y^2 }{ x^2 }$

1. hartnn

wouldn't you start by finding fz first ?

2. shamil98

the problem itself is asking for $f_{xxyzz}$ the first part is $f_x$

3. hartnn

4. hartnn

no, |dw:1388132091438:dw|

5. shamil98

oh.

6. shamil98

so the first part would be: $f_z = 4z^3y^3 \ln x$

7. hartnn

yes, continue that way ....and you'll get the same final answer :)

8. shamil98

alright, ty :)

9. hartnn

welcome ^_^