differentiation (1 Viewer)

[sammie]

ok i am haing troubles with this question.
differentiate:

y=x^4(9x-1)^5

NOw i understand how to differentiatiate
like to get this

x^4.45(9x-1)^4 + (9x-1)^5.4x^3
but i don't understand how to get to

x^3(9x-1)^4(81x-4)

can someone please explain thanks.

 

[PoLaRbEaR]

take x^3(9x-1)^4 out as a common factor and then simplify...

 

[chriswong]

y = x^4(9x-1)^5
dy/dx = (9x-1)^5.4x^3 + x^4(45(9x-1)^4)
= ((9x-1)^4(x^3))((36x-4)+45x)
= x^3(9x-1)^4(81x-4)

 

[iambored]

yeah what they said:
= x^3(9x-1)^4 (36x-4+45x)
= x^3(9x-1)^4 (81x-4)