Question

1. Let f(x)=x^3-2x. Simplify the expression f(x+h)-f(x)/h

Answer 1

Seems you are using definition of a derivative

Answer 2

first you should find f(x+h)
so replace f(x) <---x in this equation by x+h

Answer 3

You have to plug in (x+h) wherever there is an x in your function

Answer 4

\[\frac{ (x+h)^3-2(x+h)-x^3-2x }{ h }\] so this

Answer 5

You can do the simplification I think you just might have had trouble with the set up, I hope that helps.

Answer 6

\[\huge\rm f(\color{red}{x})= x^3-2x \]
substitute x+h

Answer 7

\[\huge\rm \frac{ (x+h)^3-2(x+h)- \color{blue}{(}x^3-2x\color{blue}{)} }{ h }\]
parentheses!!!

Answer 8

Good call! :)

Answer 9

so x^3-2x is the answer?? @Nnesha

Answer 10

nope how did you get that ?

Answer 11

never mind, can you help me get the answer

Answer 12

okay first solve this (x+h)^3

Answer 13

x+h^3

Answer 14

ahh nope
(x+h)^3 is same as (x+h)(x+h)(x+h)

Answer 15

so either foil that or you can use this rule
\[\rm (a+b)^3 = a^3 +3a^2b+3ab^2+b^3\]