Maths Method Unit 1/2 question

[noregret]

I am currently going through Chapter 3 Cubics especially 3H from 3K.I know how to solve those questions, but I cannot graph them for some strange reason. Can anyone help me with this promblem please?

[JellyBeanz]

If you post a screenshot of the questions it will be much easier to understand where you are having the difficulties.

But here are some tips when drawing cubics

1) Find the x and y intercepts of the graph
2) Identify any repeat factors
3) Identify whether the graph is inverted or not (e.g y=-x^3)

These three things are what's needed for a basic cubic graph, if you post your questions i can perhaps help you further.

[noregret]

Thanks for your generous reply.
I can solve x-intercepts, y-intercepts and stationary points of inflection.
For example, questio 2f Chapter 3J

f: y=x^3-1
y=(x-1)^3+0
a=1
Stationary point of inflection (1,0)
y-intercept (when x=0)
y=(0-1)^3+0
y=(-1)^3+0
y=-1+0
Therefore, y=-1
y-intercept: (0,-1)
x-intercept (when y=0)
0=(x-1)^3+0
Therefore, (x-1)^3=0
Therefore x=1
x-intercept: (1,0)


I did this because this site does not allow me to upload a file that is more than 512kb.

[Syndicate]

Thanks for your generous reply.
I can solve x-intercepts, y-intercepts and stationary points of inflection.
For example, questio 2f Chapter 3J

f: y=x^3-1
y=(x-1)^3+0
a=1
Stationary point of inflection (1,0)
y-intercept (when x=0)
y=(0-1)^3+0
y=(-1)^3+0
y=-1+0
Therefore, y=-1
y-intercept: (0,-1)
x-intercept (when y=0)
0=(x-1)^3+0
Therefore, (x-1)^3=0
Therefore x=1
x-intercept: (1,0)


I did this because this site does not allow me to upload a file that is more than 512kb.

Hello there,
If you are unsure about graphing something, I would recommend you to look at this website

Good Luck 

[noregret]

Thanks for your kind reply, it has been a great help and do you know how to sketch a graph without using any electronc devices?

[Syndicate]

Thanks for your kind reply, it has been a great help and do you know how to sketch a graph without using any electronc devices?

What do you mean?

You just have to plot your x-intercept(s), y-intercept and the point of inflection (not always), and draw a cubic going through all those points. If you questions states to find the turning points, you can either use calculus to solve for them, or simply use your CAS calculator. You don't really require an electronic device to sketch the graphs.