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Iterative formula

V=(2x2+x3)0.5 V = (2x^2 + x^3)^{0.5}
An attempt is made to find the value of x when V = 10, show that a possible iterative formula to find x is:

xn+1=102+xn x_{n+1} = \frac{10}{2+x_n}

If I did:

[br]10=x2(2+x)[br]10=x2×2+x[br]102+x=x[br][br][br]10 = \sqrt {x^2 (2+x)}[br]10 = \sqrt {x^2} \times \sqrt {2+x}[br]\dfrac {10}{ \sqrt{2+x}} = x[br][br]

I guess I'm on the right lines but how do I replace the x with xn and xn+1?

Thanks!
Original post by IgorYakov
V=(2x2+x3)0.5 V = (2x^2 + x^3)^{0.5}
An attempt is made to find the value of x when V = 10, show that a possible iterative formula to find x is:

xn+1=102+xn x_{n+1} = \frac{10}{2+x_n}

If I did:

[br]10=x2(2+x)[br]10=x2×2+x[br]102+x=x[br][br][br]10 = \sqrt {x^2 (2+x)}[br]10 = \sqrt {x^2} \times \sqrt {2+x}[br]\dfrac {10}{ \sqrt{2+x}} = x[br][br]

I guess I'm on the right lines but how do I replace the x with xn and xn+1?

Thanks!


So your new value of x is given by 10(2+x)\frac{10}{\sqrt(2+x)}
so you have xn+1=10(2+xn) x_{n+1}=\frac{10}{\sqrt(2+x_n)}
Reply 2
Original post by brianeverit
So your new value of x is given by 10(2+x)\frac{10}{\sqrt(2+x)}
so you have xn+1=10(2+xn) x_{n+1}=\frac{10}{\sqrt(2+x_n)}




Aah okay so I just needed to show that xn+1 is the next value and xn the previous by placing them in the appropriate place?
Original post by IgorYakov
Aah okay so I just needed to show that xn+1 is the next value and xn the previous by placing them in the appropriate place?


Yes

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