140k views
3 votes
The value of


2 + (1)/(2 + (1)/(2 + (1)/(2 + ... \infin) ) ) \: is \\
Given answer with step by step explanation.​

User Isatu
by
4.1k points

1 Answer

4 votes


\large\underline{\sf{Solution-}}

We have to find out the value of the fraction.

Let us assume that:


\sf \longmapsto x =2 + (1)/(2 + (1)/(2 + (1)/(2 + ... \infty) ) )

We can also write it as:


\sf \longmapsto x =2 + (1)/(x)


\sf \longmapsto x =(2x + 1)/(x)


\sf \longmapsto {x}^(2) =2x + 1


\sf \longmapsto {x}^(2) - 2x - 1 = 0

Comparing the given equation with ax² + bx + c = 0, we get:


\sf \longmapsto\begin{cases} \sf a =1 \\ \sf b = - 2 \\ \sf c = - 1 \end{cases}

By quadratic formula:


\sf \longmapsto x = \frac{ - b \pm \sqrt{ {b}^(2) - 4ac } }{2a}


\sf \longmapsto x = \frac{2 \pm \sqrt{ {( - 2)}^(2) - 4(1)( - 1)} }{2 * 1}


\sf \longmapsto x = (2 \pm √(4 + 4) )/(2 * 1)


\sf \longmapsto x = (2 \pm √(8) )/(2)


\sf \longmapsto x = (2 \pm2 √(2) )/(2)


\sf \longmapsto x = 1 \pm√(2)


\sf \longmapsto x = \begin{cases} \sf 1 + √(2) \\ \sf 1 - √(2) \end{cases}

But "x" cannot be negative. Therefore:


\sf :\implies x = 1 + √(2)

So, the value of the fraction is 1 + √2.

User Ember Arlynx
by
3.6k points