Question

find the derivative of f(x)= x^2+3x-9

Answer 1

move the exponent down
2x + 3

Answer 2

thats it

Answer 3

have you ever seen where the method of f(x+h) - f(x)/h is used? if yes can you explain that way?

Answer 4

thats the limit definition

Answer 5

\[\lim_{h \rightarrow 0} \frac{ (x+h)^{2} +3(x+h) -9 - (x^{2} +3 -9)}{ h }\]

Answer 6

correct, so it's not necessary to solve the solution that way?

Answer 7

you don't need to

Answer 8

expand (x+h)^2 and 3(x+h), simplify.

Answer 9

thank you very much guys, appreciate all the help :D

Answer 10

left out an 'x'
\[\lim_{h \rightarrow0} \frac{ (x+h)^2+3(x+h)−9−(x^2+3x−9) }{ h }\]