# Differentiate using Function of a Function (Chain Rule)

• June 5th 2009, 08:42 AM
Maths_noob
Differentiate using Function of a Function (Chain Rule)
Differentiate using Function of a Function (Chain Rule)

Is this correct?

$(x^9-8)^6$

$u=x^9-2$

$du/dx=9x^8$

$y=u^6$

$dy/du=6u^5$

$dy/dx=dy/du . du/dx$

$dy/dx = 6(x^9-2)^5 . 9x^8$
• June 5th 2009, 08:45 AM
josipive
it is just:

6*( ( x^9 - 8 )^5 )*( 9*x^8 )

and not:

6*( ( x^9 - 2 )^5 )*( 9*x^8 ) // probably mistake in writing
• June 5th 2009, 08:55 AM
Maths_noob
haha yer gd point, thanks lol i beter make sure i can read and write for my exam on wednesday then