How do you use the definition of a derivative to find the derivative of $f(x)=9x-2$ ?

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Answer 1 · 2017-05-25T11:27:10

see below

the definition of a derivative

$(dy)/(dx)=Lim_(h rarr0)=(f(x+h)-f(x))/h$

for $f(x)=9x-2$

$(dy)/(dx)=Lim_(h rarr0)=(9(x+h)-2-(9x-2))/h$

$(dy)/(dx)=Lim_(h rarr0)=(cancel(9x)+9hcancel(-2)-cancel(9x)+cancel(2))/h$

$(dy)/(dx)=Lim_(h rarr0)=(9cancel(h))/cancel(h)=$

$:.(dy)/(dx)=9$

How do you use the definition of a derivative to find the derivative of f(x)=9x-2f(x)=9x-2?