# Derivative of x sqrt(6x - 1)

1st
$\displaystyle f(x)=x(6x-1)^\frac{1}{2}$

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

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#### TheCoffeeMachine

Use the product rule $\displaystyle \left[f(x)\cdot f(x)\right]' = f'(x)\cdot g(x)+g'(x)\cdot f(x)$ then the chain rule for the 'function of a function' part.

#### euclid2

use the product rule. (f.g)=f'g+g'f

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

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