Thread: Cubic function

If someone could please give me some assistance with this question, it would be very much appreciated

The graph of a cubic function cuts the x axis at (a,0) and touches the x axis when x=b. It has a y intercept of (0,a^3.b^3). Find the equation of the cubic function.

All I can think of how to start would be y= (x+a)(x-b)^2

So any help would be much appreciciated

It's actually .

Now substitute the coordinate of your intercept to solve for .

Originally Posted by Prove It

It's actually .

Now substitute the coordinate of your intercept to solve for .

ok thanks, now when i substitute it in, I'm not sure if my solving is right but i get that it equals -a^2.b

Would that be right?

Yes.

So your function is...

Originally Posted by Prove It

Yes.

So your function is...

y= -a^2.b (x-a)(x-b)^2

Originally Posted by gbooker

y= -a^2.b (x-a)(x-b)^2

Correct.