HSC 2007 Q6 b Urgent help needed (1 Viewer)

[Twickel]

Hi
Q6b , how do I find the intercepts?

please solve and show working.

 

[TCCPICHAMP]

heres the answers
(b) (i) (0,0) and (4,0).
(ii) (0,0) is a horizontal pt of inflexion.
(3,27) is a minimum T.P.
(iii) (0,0) and (2,16).
from there u should be able to work it out, if u do, it will make u remember how to do it better

 

[Twickel]

I know the rest, I just cant do (i)

please do it for me.

 

[Chinmoku03]

Sub x = 0:
f(0) = 0
So (0,0) is the point at which the curve crosses the y axis.

Sub f(x) = 0:
x⁴ - 4x³ = 0
x³(x - 4) = 0
x = 0 or x = 4
So (0,0) and (4,0) are points at which the curve crosses the x axis.