Question

Find the derivative of f(x) = 12x^2 + 8x at x = 9

256

-243

288

224

Answer 1

use the chain rule
\[\Large \frac{ d }{ dx }(x^n)=n*x^{n-1}\]

Answer 2

can u do it now?

Answer 3

Never learned a chain rule

Answer 4

ok just use the above formula
\[u ~~have ~~~f(x)=12x^2+8x\]
now using the formula
\[f'(x)=12[2.x^{2-1}]+8=12.[2x]=8=24x+8\]
now just put x=9
\[f'(x=9)=24*9+8=224\]

Answer 5

Alright, I got it now. Thanks, man!

Answer 6

yw bud !!