What am I doing wrong?

Question

anonymous · Answer

f(x) = 6x + 2 at x = 1

6(1)^2+2
8
but it's not one of my choices

anonymous · Answer

Finding the derivative

hartnn · Answer

finding the derivative of f(x) = 6x+2 at x=1 
is this your question ?
whats f(x) exactly ?

anonymous · Answer

yes that's it

anonymous · Answer

f(x)=6x+2

hartnn · Answer

whats the derivative of 6x
whats the derivative of 2
?

anonymous · Answer

I don't understand

hartnn · Answer

f(x) = 6x+2

whats the derivative of f(x) ?
f'(x) = ...

anonymous · Answer

1

hartnn · Answer

not actually

derivative of constant = 0
so derivative of 2 is 0

for 6x,

d/dx (6x) = 6 d/dx (x) = 6 

so f'(x) = 6
makes sense ?

anonymous · Answer

kind of

anonymous · Answer

Is the derivative of every constant 0?

hartnn · Answer

so f'(x) = 6
at every point, including x=1

and yes
derivative of every constant =0

anonymous · Answer

Ohh because you did 6(1)+0 right?

hartnn · Answer

yes

anonymous · Answer

and is that like the formula to find derivatives?

anonymous · Answer

d/dx (6x) = 6 d/dx (x) = 6 This one

anonymous · Answer

do i have to do that ^ can't i just replace the 2 with a zero and the x with a 1?

hartnn · Answer

$\Large \dfrac{d}{dx}x^n = n x^{n-1}$

^^ thats the general formula

hartnn · Answer

constants can be taken out of derivative

so
d/dx (6x) = 6 d/dx(x)

anonymous · Answer

how would i use that?

hartnn · Answer

and according to that formula
d/dx(x) = 1

hartnn · Answer

you just replace 'n' by the exponent of x

anonymous · Answer

so in this case the x would be one?

hartnn · Answer

example : 
if i need derivative of x^6 
we replace n by 6

d/dx(x^6) = 6 x^5

hartnn · Answer

n would be 1

anonymous · Answer

yes i meant the n

anonymous · Answer

okay it makes a bit more sense thanks for your help :)

hartnn · Answer

welcome ^_^