Hi there,

Im trying to find the real root of the equation 0.8x^3-4.2x^2+12.7=0. It is between -2(x0) and -1(x1). My problem is when i try to put the starting values(x0, x1) back into the equation to get y0 and y1 i get incorrect answers... I am easily able to do an equation such as x^5+2x^2-5=0, but not this... Can any body help me? is there something i should be doing with the decimal numbers multiplying x in the equation?

This question has nothing to do with Probability and Statistics. It will get moved to a more suitable subforum.

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1. There are two things you should never try to prove ...... the impossible and the obvious.

2. If you always do what you've always done, you'll always get what you've always got.

3. Lack of planning on your part does not constitute an emergency on my part.

4. Pressure makes diamonds.

Apologies, this is what i learn in maths with stats class is all. Where would it more suit? Calc?

I´m not sure I understand what you are asking.
The real root?
If you´re looking for the roots to the polynomial this is solved with
calculators or computers.
And there are three real roots to this equation.
I included a picture of the graph.

Attached Thumbnails

 

Thanks anyway but as it happened ive learnt to use the newton raphson method aswell and this problem can easily be solved by newton raphson rather than bisection so ill just use that!