Question

find the derivative of x^(2) +3x -5 using the definition of the derivative (i.e.) using limits

Answer 1

i guess my explanation was not good, but if you have a question i would be happy to answer it

Answer 2

satellite73 your explanation made sense except for one part.

Answer 3

why does (x + h)^(2) become x^(2) 2xh?

Answer 4

i hope that is not what i wrote

Answer 5

(x+h)^(2)-3(x+h) -5 becomes what?

Answer 6

\[(x+h)^2=(x+h)(x+h)=x^2+2xh+h^2\]

Answer 7

crap!!! I didnt think to look at it like that!!

Answer 8

FOIL

Answer 9

and so
\[(x+h)^2+3(x+h)-5=x^2+2xh+h^2+3x+3h-5\] by the distributive law

Answer 10

i was thinking x^(2) + h^(2)

Answer 11

it is the distributive law
foil is a trick math teachers play on students

Answer 12

well thats not cool

Answer 13

one more thing. why is it +3(x+h) and not -3(x+h)?

Answer 14

because you wrote
\[f(x)=x^2+3x-5\] that is why it is + and not -

Answer 15

i guess im too literal when I try to plug it into f(x) (x+h)-f(x)/h