# Derivative of x sqrt(6x - 1)

• September 4th 2010, 06:49 PM
Derivative of x sqrt(6x - 1)
1st
$f(x)=x(6x-1)^\frac{1}{2}$

so what is the derivative? ive nevewr used the function of a fnction with an x out the front.

thankyou

also does anyone know where i can find a lot of calculus question (im in year 11) or trig questions as i have an exam in 2 days that i really need to go well in
• September 4th 2010, 06:59 PM
TheCoffeeMachine
Use the product rule $\left[f(x)\cdot f(x)\right]' = f'(x)\cdot g(x)+g'(x)\cdot f(x)$ then the chain rule for the 'function of a function' part.
• September 5th 2010, 05:23 AM
euclid2
use the product rule. (f.g)=f'g+g'f

$f'(x)=1(6x-1)^{\frac{1}{2}}+x \frac{1}{2}(6x-1)^{\frac{-1}{2}}(6)$

$f'(x)=1(6x-1)^{\frac{1}{2}}+x 3(6x-1)^{\frac{-1}{2}}$