Question

Express 6+4x-x^2 in the form a-(x+b)^2, where a and b are intergers.

(i) find the coordinates of the turning point of the curve y=6+4x - x^2 and determine the nature of this turning point.

the function f is defined by f:x -> 6+4x-x^2 for the domain 0
15 years ago

Answer 1

6+4x-x^2=-(x^2-4x-6)=-{(x-2)^2 -10}=10-(x-2)^2

Answer 2

The turning point is also called stationary point. You can find it by solving f'(x)=0
where f'(x) is the derivative of the function

Answer 3

so f'(x)=4-2x
4-2x=0
x=2

Answer 4

This is a local maximum as x^2 has a - sign so it is a parabola that is facing down

Answer 5

I.. don't understand ;A; -feels stupid-

Answer 6

The range can be found by f(2)=10
That is the maximum so the function takes all values from -infinity until 10
\[(-\infty;10\]

Answer 7

]

Answer 8

Sorry I do not have time now to explain as I have to go to work :(

Answer 9

it's okay... thanks :)

Answer 10

you get this?

Answer 11

not at all. my brain is being incredibly slow today. like any other days.. >_> i don't know how a vertex matter............