Question

find the coordinates, of the top of this function:

y = x^2 + 2x

Answer 1

so you're looking for maximum huh...do you know calculus?

Answer 2

just a little bit

Answer 3

okay..good enough...do you know how to take the derivative of this thing?

Answer 4

yes

Answer 5

so what's the derivative?

Answer 6

y' = 2x + 2

Answer 7

right. now take the derivative of this thing again...if the result is positive that means it's a minimum....if it's negative then it's a maximum...

Answer 8

Y'' = 2, so its a maximum?

Answer 9

nope...it's positive..therefore it's a minimum

Answer 10

that means this graph doesnt have a maximum

Answer 11

here's a picture of the graph :D

http://www.wolframalpha.com/input/?i=y+%3D+x%5E2+%2B+2x

it doesnt have a "top"

Answer 12

ow oke

Answer 13

then i have to find the coordinates of the bottom

Answer 14

oh goodie...then it's just the minimum..

Answer 15

you have y' = 2x + 2 right?

Answer 16

now equate 2x + 2 to 0 and solve for x what do you get?

Answer 17

x = 1

Answer 18

-1*

Answer 19

ok, then just fill in -1, in the original function or in the derivative function?

Answer 20

now substitute -1 for x in y = x^2 + 2x and solve for y

Answer 21

original function

Answer 22

ok thnx now I get it

Answer 23

welcome