finding roots of equation

**rlkmg** · October 25th 2010, 12:59 PM

$y=1/squareroot(x+1)$
$y=x$
Sketch the two graphs, and indicate on your graph the location of the root r of the equation $1/squareroot(x+1)=x$ . Use algebra and show that x=r can also solve the equation $x^3+x^2=1$ . Calculate r to 5 significant figurees using simple iteration.

Im stuck in the part in bold. I can rearrange $1/squareroot(x+1)=x$ into $x^3+x^2=1$ , but how do i show that x=r can solve the equation? Thanks.

**pickslides** · October 25th 2010, 01:02 PM

Its just asking you to find a solution for x, in this case we have called it r.

So next step is to solve this $x^3+x^2=1$

Do you know how?

**rlkmg** · October 25th 2010, 01:11 PM

Thanks, do i try to solve $x^3+x^2-1=0$ ?

If so, Im not really sure how, what do i do to solve it?

**pickslides** · October 25th 2010, 01:19 PM

Yes thats what you solve.

It mentions above 'using simple iteration'. Do you know this method?

**rlkmg** · October 25th 2010, 01:28 PM

oh right, thanks, i misunderstood the questions, thanks alot!! yeap i know how to do it

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