Find the slope of the tangent line to the graph of f at the given point.

Question

erinweeks · Answer

f(x) = x2 + 5x at (4, 36)

A. 13	

B. 21	

C. 9

hartnn · Answer

could you first differentiate f(x) to get f'(x) ?
because slope is just f'(4)

erinweeks · Answer

so how would i do that though?

hartnn · Answer

you know d/dx x^n = ... ?

erinweeks · Answer

no :(

hartnn · Answer

oh, so this is the 1st time you are solving differentiation problems ... ?
you must be having a formula list right ?
search that and tell me whats derivative of x^n =...

erinweeks · Answer

i dont have my book by me right now so i looked it up and got this page http://www.math.com/tables/derivatives/more/x%5En.htm

hartnn · Answer

i know the derivative, i wanted you to find out ....so see that and tell me what is derivative of x^n ?

erinweeks · Answer

im not understanding it at all !

hartnn · Answer

.... 
d/dx x^n = n* x^ (n-1)
put n= 2 here

erinweeks · Answer

@Hero can you help?